Glossary
1-pinnate
see pinnate . (cf. bipinnate, tripinnate, quadripinnate ).
2-pinnate
see bipinnate . (cf. pinnate, tripinnate, quadripinnate ).
3-pinnate
see tripinnate . (cf. pinnate, bipinnate, quadripinnate ).
4-pinnate
see quadripinnate . (cf. pinnate, bipinnate, tripinnate ).
A
abaxial
the side of a lateral structure that faces away from the axis on which the structure is borne. In relation to fronds the abaxial suface is the lower suface. (ant. adaxial ; cf. ventral ).
abaxially
see abaxial.
abbreviated
see reduced .
abrupt
suddenly narrowed or cut off. (ant. decrescent ; cf. truncate ).
abscissent
having fronds or parts of fronds that dry and fall from the rhizome or axis during the seasons unfavourable for growth; applied to most temperate and cold climate ferns and to some tropical species that grow in seasonally dry regions. (syn. deciduous ).
abscission
the separation of major plant parts such as fronds from rhizomes or pinnae from rachises as a result of natural structural and chemical changes (see abscission layer). These changes can be a consequence of natural ageing (senescence ) or a response to desiccation or disease. (cf. abscissent; senescence ).
abscission layer
a thin region of thin-walled cells, the senescence and death of which cause the separation of two plant parts such as a stipe from a rhizome or phyllopodium, a pinna from a rachis or a pinnule from a costa . (cf. abscission, articulation, senescence ).
accessory
supplementary, applied especially to axes or lamina divisions that are in an atypical position, eg. the sessile branches subtending larger portions of the lamina in some Dicranopteris species and the sessile segments on the axes of some Pteridium species .
achlorophyllous
lacking chlorophyll. (cf. chlorophyllous ).
acicular
needle-shaped; short and sharp-pointed, such as the hairs found in the adaxial sulcus of many species of Thelypteridaceae.
acidophilous
growing or prospering in a low pH substrate, such as bog soils or soils derived from sandstone, quartzite, or granite. (cf. calcicolous ).
acrophyll
a distal, adult frond of certain hemiepiphytic ferns with heterophyllous sterile fronds, especially Teratophyllum. (cf. bathyphyll ).
acroscopic
facing or directed toward the apex of the axis on which the structure is borne. (ant. basiscopic ; cf. distal ).
acroscopically
see acroscopic .
acrostichoid
producing sporangia apparently or actually scattered on the surface of the fertile lamina , usually densely so, as in Bolbitis, Elaphoglossum and Acrostichum.
aculeate
(1) having narrowly conical, sharp-pointed projections, as the stipe bases of certain Cyatheaceae. (n. aculeus ; syn. prickly ; ant. inermous ; cf. muricate, tuberculate); (2) bearing bullae that are no higher than wide, broadly attached, and with an acute apex . (cf. colliculate, gemmulate, patellate, pustulate ).
acuminate
forming an angle of less than 30° with the two sides somewhat concave . (cf. acute, attenuate, obtuse ).
acute
forming an angle of 30–90° with the two sides straight or slightly convex . (cf. acuminate, attenuate, obtuse ).
adaxial
the side of a lateral structure that faces toward the axis on which the structure is borne. In relation to fronds the adaxial suface is the top suface. (ant. abaxial; cf. dorsal ).
adjacent
next to each other, but not overlapping or touching.
adnate
broadly attached to a dissimilar structure, such as the pinnae of a pinnatisect frond to the rachis . (cf. connate, free ).
adult
having the most fully developed morphology. (ant. juvenlle).
adventive
partially naturalized from an accidental introduction. (cf. escaped, introduced, naturalized ).
aerial
above ground. (ant. subterranean ; cf. epigeous, hypogeous ).
aerophore
an often evanescent spot, swelling, or finger-like projection of thin-walled cells found along the stipe or in the pinna or pinnule axils of some ferns, especially Thelypteridaceae, that apparently aids gas exchange with the atmosphere. (cf. hydathode ).
aggregated
clustered.
ala
a wing; a usually long, narrow membrane or section of lamina laterally bordering a stipe, rachis, or costa . (pl. alae ; adj. alate ).
allopolyploid
a polyploid whose chromosomes were contributed by two or more species . (cf. autopolyploid ).
alternate
having one structure, in ferns usually a pinna, inserted at a single point along an axis . (cf. opposite, verticillate ).
amphibious
capable of growing on dry land or in water, often applied to plants of seasonally inundated areas. (cf. aquatic, terrestrial ).
anadromic
see anadromous .
anadromous
with the basal pinnule and/or basal vein group of the pinna directed toward the frond apex . (cf. catadromous, isodromous ).
anastomosing
joining together to form a mesh or network and enclose areolae; usually applied to veins and muri . (ant. free ).
angustate
gradually narrower to the apex . (syn. gradual, tapered ; cf. decrescent ).
annulus
a row or patch of partially or entirely thick-walled cells of the capsule of the leptosporangium that contracts or breaks and permits the capsule to open and to discharge its spores. (pl. annuli ; adj. annular ; cf. stomium ).
antepenultimate
two before the last (i.e. the one immediately before the penultimate), in a series . (cf. penultimate ).
antheridia
plural of antheridium .
antheridium
the male sex organ of pteridophytes borne on the gametophyte and producing spermatozoids. (pl. antheridia ; cf. archegonium ).
antherozoid
see spermatozoid .
apex
the distal, terminal portion of a structure. (pl. apices ; adj. apical ; syn. tip ; ant. base ).
aphlebia
a highly divided, skeletonized, anomalous, pinna-like structure on the stipe of certain ferns, especially in Cyatheaceae. (pl. aphlebiae ).
apical
at or pertaining to the apex or tip , especially of complex structures or organs like roots, rhizomes, or fronds. (n. apex ; n.pl. apices ; ant. basal ; cf. lateral, terminal ).
apiculate
abruptly terminating in a small, triangular apex . (cf. cuspidate, mucronate ).
apogamy
the formation of a sporophyte from a gametophyte by direct asexual development rather than by fertilization of gametes. (adj. apogamous ).
approximate
closely spaced, and so nearly touching. (cf. contiguous, distant, imbricate ).
aquatic
growing in water, rooted in the substrate or free -floating. (cf. amphibious, rheophytic, terrestrial ).
arborescent
having the habit of a tree, with an obvious caudex, found especially in many species of Cyatheaceae.
archegonia
plural of archegonium .
archegonium
the female sex organ of pteridophytes borne on the gametophyte and producing ova . (pl. archegonia ; cf. antheridium ).
areola
(1) an area enclosed by a ring of veins and with or without one or more free included veinlets; (2) also used to describe spore onamentation in which areas of the spore surface are enclosed by muri (see retate ).
areolate
having areas enclosed by a mesh or network of anastomosing veins. (n. areola ; n.pl. areolae ).
arista
a long, stiff, bristle-like apical prolongation of a midrib beyond the margin, as on the apices of segments in Arachnoides and Polystichum (adj. aristate ; pl. aristae ).
aristate
bearing a long, stiff, bristle-like apical prolongation of a midrib beyond the margin, as on the apices of segments in Arachnoides and Polystichum (n. arista ; n.pl. aristae ; cf. mucronate ).
articulate
having an articulation . (syn. jointed ; ant. exarticulate ).
articulation
in some ferns, a swollen joint-like abscission zone (containing an abscission layer) at the junction of a stipe and rhizome, a stipe and phyllopodium or a rachis and pinna; (2) an obvious , thickened, discoloured, weakened, or constricted area at the nodes of Equisetum stems or proximal to the nodes of some Selaginella stems that may serve to fragment the plant and promote its dispersal. (adj. articulate ; syn. joint ; cf. abscission layer).
artificial group
see paraphyletic, polyphyletic . (ant. natural group ).
ascending
(1) at an angle from within the substrate, usually a short rhizome that bears approximate stipe bases, usually on all sides. (cf. erect, repent (creeping)); (2) obliquely directed away from a surface and towards the apex of the structure on which it is borne. (cf. appressed, patent, reflexed ).
aspidote
bearing peltate scales. (cf. furfuraceous, paleaceous , squamous).
asymmetric
having a different outline on each side of a central axis . (ant. symmetric ).
atrocastaneous
dark brown tinged with red; dark chestnut-coloured.
atropurpureous
purplish-black.
auricle
a rounded or sometimes elongate lobe or ear, usually at the base of a lamina, pinna, or pinnule or along the stipe . (adj. auriculate ).
auriculate
having one or more auricles. (n. auricle ; ant. exauriculate ).
autoallopolyploid
an allopolyploid whose chromosomes have doubled.
autopolyploid
a polyploid whose chromosomes were contributed by only one species . (cf. allopolyploid ).
awn
in ferns, a small, slightly flattened, bristle-like appendage on the adaxial side of a rachis or costa , found especially in certain Pteris species .
B
baculate
bearing stelae that are at least 1.5 x longer than wide, cylindrical, and with usually an obtuse to round apex . (cf. clavate, echinate, saccate, tuberculate, verrucate ).
base
the proximal portion of a structure, that part nearest the point of attachment. (adj. basal ; ant. apex ).
basionym
a valid name whose epithet is transferred when making a new combination .
basiscopic
facing or directed toward the base of the axis on which the structure is borne. (ant. acroscopic ; cf. proximal ).
basiscopically
see basiscopic .
bathyphyll
a proximal, juvenile frond of certain hemiepiphytic ferns with heterophyllous fronds, especially Teratophyllum. (cf. acrophyll ).
biauriculate
bearing two auricles, eg. the rhizome scales or pinnae of certain Polypodiaceae. (cf. uniauriculate ).
bicellular
formed of two cells. (cf. unicellular, paucicellular, multicellular ).
bicolorous
having two colors, usually applied to rhizome scales that have a central stripe or region that is decidedly different in color from the borders. (ant. concolorous ).
bifid
divided into two similar parts, but not nearly to the base . (cf. bipartite, quadrifid, quadripartite ).
bifurcate
divided once into two equal or subequal branches, applied especially to laminae and to simply branched hairs. (syn. forked ; cf. stellate). The term twice-bifurcate is applied to more complex hairs that branch dichotomously twice. i.e. they fork above the base (from the apex of the pedicel) into two arms, and each arm forks into two equal or subequal rays. (cf. stellate, twice-stellate ).
bilabiate
two-lipped, usually applied to the involucres of Hymenophyllum and some species of Trichomanes and to the indusia of some other genera.
bilateral
symmetrical on opposite sides of an axis . (cf. unilateral ).
bipartite
divided into two similar parts to or nearly to the base . (cf. bifid, quadrifid, quadripartite ).
bipinnate
divided into pinnae bearing pinnules that are more-or-less entire . (cf. pinnate, quadripinnate, tripinnate ).
bipinnatifid
pinnate with pinnae lobed more than half way to their costae .
bipinnatisect
divided into pinnae with the pinnae pinnatisect . (syn. pinnate-pinnatisect ).
biseriate
disposed in two rows. (cf. multiseriate, uniseriate ).
bisulcate
having two longitudinal grooves, especially on the adaxial side of the stipe, rachis, or costa . (cf. sulcate, trisulcate ).
bivalvate
having or consisting of two valves or similar parts as the involucres of many Hymenophyllaceae, the indusia of Cibotium or the sporangia of Osmundaceae.
border
the marginal and submarginal parts of a structure, especially of bicolourous scales. (cf. central band, margin ).
branch
(1) a subordinate division from a main stem; in Equisetum, one of few to many small stems forming whorls at intervals along the larger, main stem. (adj. branched ; dim. branchlet); (2) in the Gleicheniaceae, an axis subtending a bud, formed in pairs and further designated by its order (ultimate, penultimate, or antepenultimate) and whether it bears segments (pectinate, partially pectinate, or nude ).
bristle
a stiff, paucicellular, usually straight, terete, and dark-coloured epidermal outgrowth one cell wide distally and often a few cells wide at the base . (adj. bristly ; cf. scale, squamule ).
brittle
breaking or shattering easily when bent.
bud
in pteridophytes, a non-deciduous, unspsecialized, multicellular, often irregular mass of tissue produced by a gametophyte that grows and forms an apogamous sporophyte . (cf. bulbil, gemma ).
bulbiferous
bearing one or more bulbils. (n. bulbil ; syn. viviparous ; cf. gemmiferous ).
bulbil
a small, usually persistent, more or less globular, usually hairy or scaly, asexual propagule borne on a rachis or costa or occasionally a lamina margin that is capable of forming a plantlet before, during, or after frond senescence, or after separation from the frond , as in certain Asplenium, Bolbitis, Diplazium, Polystichum and Tectaria species . (adj. bulbiferous ; syn. bulblet ; cf. bud, gemma ).
bulla
a general term for a radially symmetrical low protuberance (no higher than wide); usually applied to spore ornamentation and the basis of many more specialized terms such as aculeate, colliculate, gemmulate and pustulate . (cf. stela, murus, cavus ).
C
caducous
early deciduous , even prior to the maturation of the structure on which it is borne. (syn. fugacious ; cf. deciduous, persistent ).
caespitose
growing in tufts.
calathiform
having the aspect of a narrow-bottomed vase or shuttlecock, with a cluster of fronds arising from a short, erect rhizome, as in some species of Dryopteris. (cf. nidiform ).
calcicolous
growing or prospering in a high pH substrate, such as soils derived from limestone or dolomite. (cf. acidophilous ).
campanulate
bell-shaped; usually applied to the involucres of some Hymenophyllaceae, especially species of Trichomanes and Vandendoschia. (cf. peltate, pseudopeltate, bilabiate ).
canaliculate
channeled; having a small groove, especially on the adaxial side of a costule or costulet . (cf. sulcate ).
capitate
terminated by a bulbous to spherical swollen area (in unicellular glands) or cell (in multicellular glands).
capsule
the subspherical, ovoid, or slightly angular part of a sporangium that contains the spores. (cf. pedicel ).
carina
a sharp, longitudinal ridge, as on the abaxial side of the midrib in some species of Asplenium and Loxogramme. (adj. carinate ; syn. keel ).
cartilaginous
thick and slightly flexible.
castaneous
medium brown tinged with red; chestnut-coloured.
catadromic
see catadromous .
catadromous
with the basal pinnule and/or basal vein group of the pinna directed toward the frond base . (cf. anadromous, isodromous ).
catenate
like a chain composed of links; in hairs, with adjacent cells collapsed at right angles to each other and often the end walls of the cells thickened or dark-coloured, as on some Ctenitis fronds. (syn. ctenitoid, jointed ).
caudex
an erect, trunk-like rhizome found in arborescent and subarborescent ferns, such as Cyathea and some species of Diplazium. (pl. caudices ).
cavifom
having cavi ; a general term encompassing several more specialized terms. (cf. bulliform, muriform, steliform )
cavus
a general term for a shallow, steep-sided, indentation (crater); usually applied to spore ornamentation and the basis of several more specialized terms such as foveate and foveolate . (pl. cavi ; cf. bulla, murus, stela ).
central band
the differently coloured and often thickened central cells of bicolorous scales (cf. border ).
character
a feature of an organism. (syn. characteristic, character state).
character state
see character .
characteristic
see character .
chartaceous
having the texture of thick and rigid writing paper. (cf. coriaceous, membranaceous, papyraceous ).
chlorophyllous
green because it contains chlorophyll.
chromosome
one of a definite number of bodies bearing hereditary information (DNA) that divide and are usually equally partitioned into daughter cells during cell division .
ciliate
bearing flexible, thin, usually straight hairs, as the microphyll margins of many Selaginella species . (n. cilium ; n.pl. cilia ; dim. ciliolate ; ant. eciliate ; cf. cincinnate, setose ).
ciliform
having the form of a cilium, a flexible, thin, often straight marginal hair (n. cilium ; n.pl. cilia ; cf. setiform ).
cincinnate
bearing soft, somewhat curly hairs, such as the rhizome scales of certain species of Sticherus and Oleandra. (cf. ciliate, setose ).
circinate
having an apical spiral in a single plane with the axis and with the developing apex at the center of the spiral, the typical vernation of ferns. (cf. convolute ).
circular
see orbiculate . (cf. rounded ).
clathrate
lattice-like; having thick lateral (adjacent) cell walls and thin surficial walls, especially applied to rhizome scales of Asplenium, Ctenitis and some Polypodiaceae and Pteridaceae.
clavate
(1) club-shaped; round at the apex, widest just below the apex, and tapering gradually to the base; (2) bearing stelae that are narrow, higher than wide, and widest at or near their obtuse apex . (cf. baculate, echinate, saccate, tuberculate, verrucate ).
clubmoss
a common name for any species in the lycophyte family Lycopodiaceae (which in Thailand is represented by Lycopodium, Lycopodiella and Huperzia).
coalescent
fusing; marked uniting of originally separate structures during their subsequent development. (cf. confluent, connivent, discrete ).
coenoindusium
a laterally elongate indusium or pseudoindusium protecting a coenosorus . (cf. indusium; pseudoindusium ).
coenosori
plural of coenosorus .
coenosorus
a compound sorus composed of several contiguous sori fused end-to-end (pl. coenosori ; cf. synangium ).
colliculate
bearing bullae that are contiguous, broadly attached, no higher than wide, and with an obtuse to round apex . (cf. aculeate, gemmulate, patellate, pustulate ).
combination
a name consisting of a generic name and one or two epithets below that level, one at the species level sometimes followed by one below the species level.
commissural
joined or seamed; in ferns, a commissural vein joins parallel, otherwise free veins along the lamina margin and often underlies a continuous, marginal coenosorus . (n. commissure ).
commissure
see commissural .
complanate
(1) flattened, usually in a horizontal plane, such as that of a lamina ; (2) at the same level as the surface. (syn. flush ; cf. immersed, impressed, prominulous, superficial ).
complete
fully developed over its usual length or area. (ant. incomplete ).
compound
composed of two or more similar parts; in laminae, pinnate or more divided. (cf. decompound, simple ).
concolorous
being completely or nearly uniform in color. (ant. bicolorous ).
conduplicate
having approxirnately equal lateral halves folded together abaxially .
confluent
converging; growing near to and eventually touching, commonly applied to sori . (cf. coalescent, connivent, discrete ).
conform
(1) similar in shape and size to others, commonly applied to an apical pinna in comparison with the lateral pinnae . (ant. difform); (2) having all cells of the body similar in shape and orientation, as the rhizome scales of Sphaeropteris. (cf. marginate ).
congested
crowded; accumulated into a point or region.
connate
joined, usually laterally, to a similar structure, such as the fusion of pinnae towards the apex of a frond or the fusion of pinnules towards the apex of a pinna . (cf. adnate, free ).
connivent
coming together, but not joined, commonly applied to veins from two or more vein groups that approach one another, often at a sinus , but do not join. (cf. coalescent, confluent, discrete ).
contiguous
having the parts touching. (cf. approximate, distant, imbricate ).
continuous
not interrupted or broken. (ant. interrupted ).
contorted
irregularly twisted; distorted.
contracted
narrowed or shortened, often applied to subdimorphic fertile laminae or pinnae . (ant. expanded ).
convolute
having two lateral spirals opposite each other, one from each edge of an axis (as seen in transverse section), without apices developing at their center, the typical vernation of Ophioglossum. (cf. circinate ).
cordate
heart-shaped; or bearing a pair of broadly rounded , sometimes overlapping lobes. (cf. hastate, sagittate ).
cordiform
heart-shaped.
coriaceous
leathery in texture and thick. (cf. chartaceous, membranaceous, papyraceous ).
correct
the legitimate name that must, under the Code (ICBN), be adopted for a taxon with a particular rank, position, and circumscription. (ant. incorrect ; cf. legitimate, valid ).
costa
the major axis of a pinna. Some authors prefer to use the term pinna-rachis instead of costa when the pinna is pinnate or more divided. (syn. pinna-rachis ; pl. costae ; adj. costal ; cf. costule, costulet ).
costal
along the costa, costule, or midrib . (cf. inframedial, intramarginal, marginal, medial, supramedial ).
costulate
having a costule . (ant. ecostulate ).
crenate
having rounded teeth; shallowly scalloped in a single plane . (dim. crenulate ; cf. dentate, serrate ).
crenulate
diminutive of crenate.
cristate
bearing muri that are narrow, sharp-edged, non-anastomosing, and do not form areolae . (n. crista ; n.pl. cristae ; cf. retate, reticulate, rugate ).
cross-section
see transverse section. (cf. longitudinal section ).
cross-vein
see transverse .
cuneate
wedge-shaped; forming an angle of 30—45° with the two sides straight.
D
decaploid
a plant that has ten sets of chromosomes.
deciduous
detaching, usually between maturity and senescence . (cf. caducous, abscissent, persistent ).
decompound
several times divided; in laminae, those that are tripinnate or more divided. (cf. compound, simple ).
decumbent
lying on the substrate and mostly rooted, except with the apex erect or ascending . (cf. procumbent, prostrate, sarmentose ).
decurrent
extending basiscopically on and adnate to an axis . (cf. surcurrent, sursumcurrent ).
dehiscent
splitting open or capable of doing so. (ant. indehiscent ).
deltate
broadly triangular with an obtuse apex .
dentate
having usually broad teeth that are directed outward from the margin, not acroscopically . (dim. denticulate ; cf. crenate, entire, serrate, toothed ).
denticulate
bearing small teeth formed by prolongations of one or two cells of the scale margin as in some Diplazium; also said of clathrate scales in which the end walls of the marginal cells are thickened and so appear to be teeth, as in Aspleniaceae.
depauperate
dwarfed in development due to poor growing conditions.
description
a lengthy statement (in Latin for new taxa) of the characters of a taxon that permit a reader to develop a mental image of the taxon . (cf. diagnosis ).
determinate
genetically limited in growth, and so usually regular in size or shape. (ant. indeterminate ).
diagnosis
a brief statement (in Latin for new taxa) emphasizing the distinctive characters of a taxon that distinguish it from related taxa . (cf. description ).
diaphanous
see translucent, transparent .
dichotomous
(1) in relation to frond complexity: a pattern of branching in which there are only two branches at each fork and the two branches are equal (more-or-less) in size, shape, and position, such as in Psilotum (n. dichotomy ; cf. pseudodichotomous); (2) in relation to venation: a branching pattern in which the two veins resulting from each fork are free and more-or-less equal. (n. dichotomy ; cf. pinnate )
dichotomy
see dichotomous .
difform
different in shape and/or size from others, commonly applied to an apical pinna in comparison with the lateral pinnae . (ant. conform ).
digitate
having four or more divisions all radiating narrowly from a single point, somewhat like the fingers of a hand. (cf. palmate, ternate ).
dimidiate
halved diagonally, with usually one half rudimentary or partially absent, as the pinnae or pinnules of certain Adiantum and Lindsaea species .
dimorphic
having two shapes or sizes, commonly applied to fertile versus sterile laminae or portions of laminae. (cf. hemidimorphic, monomorphic, polymorphic, heterophyllous).
diploid
a plant that has two sets of chomosomes.
discrete
separate. (cf. coalescent, confluent, connivent).
dissected
deeply divided into many parts.
distal
toward or near the apex. (cf. acroscopic, medial, proximal).
distant
having similar parts that are well separated and not overlapping or touching, usually applied to stipes, pinnae, pinnules, or segments. (syn. remote; cf. approximate, contiguous, imbricate).
divaricate
widely divergent; inclined markedly away from each other. (cf. divergent, spreading).
divergent
inclined somewhat away from each other. (cf. divaricate, spreading).
division
a major category of plants, such as Tracheophyta (all vascular plants) or Pteridophyta (all spore-bearing vascular plants).
dodecaploid
a plant that has twelve sets of chromosomes.
dormant bud
in the Gleicheniaceae, a bud borne at the apex of an axis that is flanked by two branches; it does not break dormancy and so terminates its axis. (cf. latent bud).
dorsal
the upper side of a horizontal axis, such as a creeping rhizome, or of a plane non-vascular structure, such as a gametophyte. (ant. ventral; cf. abaxial, adaxial).
dorsifixed
attached by the back (not by the base), such as the elongate rhizome scales of some species of Campyloneurum. (cf. basifixed, peltate).
E
echinate
bearing stelae that are higher than wide, narrowly conical, widest near the base, and with an acute to attenuate apex. (dim. echinulate; cf. baculate, clavate, saccate, tuberculate, verrucate).
echinulate
diminutive of echinate.
eglandular
not glandular.
elaminate
lacking expanded lamina tissue, sometimes by reduction entirely to axes, as in the fertile portions of Osmunda fronds. (ant. laminate).
elater
each one of four strap-shaped appendages found on Equisetum spores.
ellipsoid
a solid structure that is elliptical in longitudinal section.
elongate
longer than wide, from slightly to greatly so. (cf. isodiametric).
elongate-reniform
see hippocrepiform; a reniform indusium that is elongate (or horse-shoe shaped), compared to a reniform indusium that is more circular. (syn. hippocrepiform; cf. round-reniform).
emarginate
having a broad and shallow sinus at the nearly truncate apex of a segment, lobe, or tooth. (cf. retuse).
endemic
having a restricted distribution compared with a larger area, such as being confined to a single locality, country, or region.
endospore
the inner, pectocellulose layer of the spore wall that lies between the cytoplasmic membrane that surrounds the contents of the spore and the exospore. (syn. intine; cf. epispore, exospore, perispore).
entire
having an even or smooth margin (not toothed or lobed) and with or without marginal hairs or cilia. (cf. crispate, repand, sinuate, undulate).
epidermis
the outermost layer of cells of the plant that lacks intercellular spaces, contains stomates, and serves to protect the plant, to selectively exchange gases, and to retard water loss by producing a wax-like cuticular layer or by being impregnated with a wax-like substance. (adj. epidermal).
epigeous
growing above or on the surface of the ground, commonly applied to horizontal rhizomes. (ant. hypogeous; cf. subterranean, aerial).
epipetric
see lithophytic.
epiphyte
see epiphytic. (cf. hemiepiphyte, hemiepiphytic).
epiphytic
growing on another plant, usually the trunk or branches of a shrub or tree. (n. epiphyte; cf. hemiepiphytic).
epispore
an outer, sporopollenin layer of the spore wall that is external to the exospore in some heterosporous ferns and Equisetum. (cf. endospore, exospore, perispore).
epithet
a typically descriptive or commemorative word, usually an adjective but sometimes a noun in apposition, that is combined with the name of a genus to form the name of a taxon, or with the name of a species to form the name of an infraspecific taxon.
equilateral
equal on both sides of an axis. (ant. inequilateral).
erect
vertical or upright from within the substrate, often producing a cluster of fronds in a basket or shuttlecock-like arrangement, with approximate stipe bases on all sides. (cf. ascending, repent (creeping)).
escaped
partially naturalized after a deliberate introduction. (cf. adventive, introduced, naturalized).
eusporangia
plural of eusporangium.
eusporangiate
having eusporangia, not leptosporangia. (ant. leptosporangiate).
eusporangium
found in all vascular plants including lycophytes but excluding most ferns, a thick-walled, thick-pedicelled sporangium bearing thousands of spores, and lacking an annulus. (pl. eusporangia, adj. eusporangiate. cf. leptosporangium). Eusporangia are found only in 4 fern families: Equisetaceae, Marattiaceaee, Ophioglossaceae and Psilotaceae.
evanescent
(1) completing its growth cycle in a short period of time, such as species adapted to seasonally wet habitats. (2) said of structures that are conspicuous for a short period and then disappear, such as the aerophores of some species.
exarticulate
lacking an articulation. (ant. articulate).
exauriculate
lacking an auricle or auricles. (ant. auriculate).
excurrent
running or pointing towards the margin, or outwards or away from the point of origin, usually applied to veinlets. (cf. recurrent).
exhydathodous
lacking hydathodes. (ant. hydathodous).
exospore
the middle, principal sporopollenin layer of the spore wall, external to the endospore and internal to the perispore. (syn. exine; cf. endospore, epispore, perispore).
exotic
not native (indigenous). (cf. native (indigenous)).
expanded
increased in area or size. (ant. contracted).
exserted
projecting beyond another structure, applied especially to the filiform receptacle of many Trichomanes species.
F
false vein
see venuloid.
family
the principal rank of taxa between order and genus; the totality of genera that are more closely related to one another than they are to any other genera of other families.
farina
a white, yellow, or other coloured, usually thick, powdery-appearing exudate of glands, especially on the underside of the lamina in Pteridaceae. (adj. farinose).
farinose
having a white, yellow, or other coloured, usually thick, powdery-appearing exudate of glands, especially on the underside of the lamina in Pteridaceae. (n. farina; syn. ceraceous; cf. glaucous, pruinose).
fasciculate
in a closely set cluster, as if from a single point, commonly applied to hairs or stipes.
fern
see monilophyte.
fern-allies
a popular but outdated term used for a paraphyletic assemblage of spore-bearing (seedless) vascular plants that were all believed to be closely related to true ferns. The term referred to horsetails, whisk ferns, quillworts, clubmosses and spikemosses. Nowadays, horsetails and whisk ferns are regarded as true-ferns (monilophytes) and the quillworts, clubmosses and spikeworts (now collectively called lycophytes) are believed to be very distantly related to these. (cf. lycophytes, monilophytes, pteridophytes).
ferrugineous
rust-coloured.
fertile
(1) in relation to sporophytes: producing sporangia and presumably viable spores. (ant. sterile); (2) in relation to gametophytes: producing gametes and/or gametangia. (ant. sterile).
fibrillose
appearing to be composed of fibers, as the rhizome scales of many Dryopteridaceae.
filamentose
a modifying term indicating the presence of long filaments borne on the principal surface ornamentation, as in Lecanopteris.
filamentous
composed of or resembling thread-like structures, such as the gametophytes of Trichomanes. (ant. thalloid).
fimbriate
a modifying term indicating the presence of elaborated processes at the apex of projecting ornamentation, as the cristate-fimbriate spores of certain Elaphoglossum and Oleandra species.
flabellate
fan-shaped or fan-like; used to describe frond shape or venation (i.e. veins of equal size radiating from a single point without a prominent central axis).
flaccid
limp or flabby.
flexuous
curved or bent slightly in alternate directions; gently zig-zag. (cf. fractiflex).
flush
see complanate.
form
a rank of taxa subordinate to the species and used for minor variants, such as different colour forms, that are scattered throughout the geographic range of the species; commonly the lowest category in the hierarchy of infraspecific taxa.
fossulate
bearing muri that are long, low, and parallel, with sulci between them that are narrower than the muri, as in the spores of Anemia. (cf. pleurate, rivulate).
foveate
bearing cavi that are round or nearly so and separated by distances approximating their diameter. (cf. foveolate).
foveolate
bearing cavi that are round or nearly so and are separated by distances much greater than their diameter. (syn. pitted. cf. foveate).
fractiflex
bent strongly in alternate directions; decidedly zig-zag. (cf. flexuous)
free
(1) not joined or attached to a similar or different structure. (cf. adnate, connate); (2) of veins: not anastomosing or otherwise joined. (ant. anastomosing).
frond
the photosynthetic organ of ferns, usually consisting of a stipe and lamina, characterized by its often large size and usually highly branched vascular system. (cf. microphyll).
furfuraceous
bearing thin, minute, occasionally amorphous scales, sometimes mixed with hairs, often in a mat. (cf. aspidote, paleaceous, squamous).
G
gametangia
plural of gametangium.
gametangium
a structure in which gametes are formed; in ferns, archegonia (female) and antheridia (male). (pl. gametangia).
gamete
a sex cell, in pteridophytes, spermatozoids (male) and ova (female).
gametophyte
an inconspicuous, non-vascular plant that bears gametangia and gametes. In homosporous pteridophytes, they are surficial, thin, chlorophyllous, and filamentous, ribbon-like, or heart-shaped, or somewhat stellate or are subterranean, massive, achlorophyllous, and globular, cylindrical, or branched. In heterosporous pteridophytes, they are much reduced structures borne (and partially developing) within spore walls. (syn. prothallus; cf. sporophyte).
gemma
(1) a markedly abscissent, structurally specialized, often glabrous, asexual propagule found on some sporophytes that detaches and forms a plantlet after dispersal; (2) a markedly abscissent, structurally specialized, paucicellular, asexual propagule found on some gametophytes that detaches and forms a new gametophyte after dispersal (pl. gemmae; adj. gemmiferous; cf. bulbil, bud).
gemmiferous
bearing one or more gemmae. (n. gemma; n.pl. gemmae; cf. bulbiferous).
gemmulate
bearing bullae that are no higher than wide, slightly to greatly contracted at the base, and with a round apex. (syn. papillate, saccate; cf. aculeate, colliculate, patellate, pustulate).
genus
a rank of taxa intermediate between family and species; the totality of species that are more closely related to one another than they are to any other species of other genera.
glabrescent
becoming glabrous with age.
gland
a unicellular or paucicellular and one cell wide, filiform, clavate, capitate, or globular epidermal structure containing or secreting resinous or wax-like, often highly coloured substances. (adj. glandular; cf. hair, paraphysis).
glandular
bearing glands. (n. gland; syn. glanduliferous)
glaucous
having the surface very thinly covered and not obscured by a bluish or whitish, wax-like coating, such as the laminae of some Cyathea, Microlepia, Selliguea and Dennstaedtiaceae species (cf. farinose, pruinose).
gradate sorus
see sorus.
gradual
see decrescent, angustate.
granulate
a modifying term indicating the presence of rather amorphous, minute, grain-like bodies deposited on the surface of the principal ornamentation.
H
hair
a unicellular, paucicellular, or multicellular, linear or rarely branched epidermal outgrowth composed of a single elongate cell or of one or more separate files of cells one to several cells long. (adj. hairy; cf. gland, paraphysis).
hamate
having a small hook at the apex, usually applied to hairs, especially in Thelypteridaceae. (cf. uncinate).
haploid
a plant that has one set of chromosomes.
hastate
having the shape of an arrowhead, with laterally directed basal lobes. (dim. hastulate; cf. cordate, sagittate).
helicoid
branching repeatedly only on the basiscopic side of the principal axis, and so appearing to have a dichotomously branched rachis, found in a few species of Adiantum. (cf. spiralled).
hemidimorphic
partially dimorphic, either longitudinally or laterally, commonly applied to laminae. (cf. dimorphic, monomorphic, polymorphic).
hemiepiphyte
see hemiepiphytic (cf. epiphyte, epiphytic).
hemiepiphytic
in pteridophytes, having a long-creeping rhizome or indeterminate rachis so that the plant remains rooted in the ground and climbs tree trunks, as in some species of Lindsaea, Lomariopsis, Lomagramma, Neocheiropteris, Stenochlaena, Teratophyllum and Trichomanes. (n. hemiepiphyte; cf. epiphytic).
hemitelioid
having the form of a shallow saucer, usually firm and fully or partially surrounding the sorus, typical of certain Cyatheaceae.
herbaceous
rather thin and soft in texture.
heterodromous
with the basal portions of the lamina differing in dromy from the apical portions.
heterophyllous
having fronds (in ferns) or microphylls (in lycophytes) of two or more different shapes. (syn. dimorphic, polymorphic).
heterosporous
producing spores of two sizes, each of which develops gametophytes having gametangia of a single sex. (ant. homosporous).
hexaploid
a plant that has six sets of chromosomes.
hippocampiform
seahorse-shaped; shallowly crescent-shaped with rounded ends. (cf. hippocrepiform, reniform, round-reniform, elongate-reniform).
hippocrepiform
horseshoe-shaped; deeply crescent-shaped with rounded ends. (syn. elongate-reniform; cf. hippocampiform, reniform, round-reniform).
hirsute
bearing straight, erect, decidedly stiff and relatively coarse hairs. (dim. hirsutulous; dim.syn. hirtellous).
hirsutulous
diminutive of hirsute. (syn. hirtellous; cf. hirsute).
hirtellous
see hirsutulous.
holotype
the one specimen or other element of the protologue (usually an illustration) used (and usually cited) by the author to prepare the diagnosis or description of a new species.
homonym
a name identical to another name, but based on a different type and usually published by a different author.
homosporous
producing spores of a single size, which develop gametophytes that bear gametangia of one or two sexes. (ant. heterosporous).
homotypic synonym
see synonym.
hyaline
very thin, translucent, and colourless. (cf. scarious).
hydathode
a commonly elevated or sunken, dark or sometimes pale area of the epidermis on the adaxial (top) surface of the lamina that coincides with the end of a vein and exudes water and salts (adj. hydathodous; cf. aerophore, lime dot).
hydathodous
having hydathodes. (n. hydathode; ant. exhydathodous).
hypogeous
growing under the surface of the ground, commonly applied to horizontal rhizomes. (ant. epigeous; cf. subterranean, aerial).
I
ICBN
the International Code of Botanical Nomenclature.
idioblast
a specialized cell, manifestly different from and scattered among the typical cells of a tissue. (cf. spicular cell).
illegitimate
a validly published name that is contrary to one or more articles of the Code (ICBN), and so must be rejected. (ant. legitimate).
imbricate
overlapping, commonly applied to similar structures like rhizome scales, pinnae, pinnules, or microphylls. (cf. approximate, contiguous, distant).
immersed
within lamina tissue, and so not readily seen upon cursory examination. (cf. complanate, impressed, prominulous, superficial).
imparipinnate
pinnate and terminated by a single pinna similar to the lateral ones. (ant. paripinnate).
impressed
at a level below the surface of lamina tissue, but not completely immersed in it, thus readily seen upon cursory examination. (syn. sunken; cf. complanate, immersed, prominulous, superficial).
incomplete
not fully developed over the usual length or area. (ant. complete).
indehiscent
not splitting open or capable of doing so. (ant. dehiscent).
indeterminate
genetically unlimited in growth, and so usually irregular in size or shape; in ferns, often applied to the rachis or other axes, as in Lygodium. (ant. determinate).
indigenous
see native.
indurated
becoming hard and thick.
indusiate
having indusia. (n. indusium; n.pl. indusia; ant. exindusiate).
indusium
a usually thin, often scale-like, extrorse or rarely introrse epidermal membrane, or a structure subtending the sorus, that partially or fully protects the young sporangia. (pl. indusia; cf coenoindusium, pseudoindusium).
inequilateral
not equal on both sides of an axis. (ant. equilateral).
inframedial
proximal to the middle; applied to sori that are a little closer to the costa or costule than to the margin. (cf. costal, intramarginal, marginal, medial, supramedial).
internode
the portion of a stem between two nodes, especially in the stems of Equisetum.
interrupted
not continuous; broken by intervening incisions, breaks in venation, or other causes, such as a linear sorus interrupted by incisions in the lamina margin. (ant. continuous).
intramarginal
near the margin, often applied to sori. (cf. costal, inframedial, marginal, medial, supramedial).
intricate
entangled, commonly applied to hairs.
introduced
imported accidentally or intentionally from another place or country. (cf. adventive, escaped, naturalized).
introrse
facing away from or opening away from the margin (toward a central axis) or apex (basiscopically), usually applied to indusia. (ant. extrorse).
invalid
a name that is not valid; i.e. a name that is not published in accordance with the articles of the Code (ICBN) governing the publication of a name. (ant. valid).
invasive
naturalized and capable of spreading rapidly, even to the detriment of native species or vegetation, such as certain species of Blechnum, Cyathea, Lygodium, and Cyclosorus.
involucral
pertaining to an involucre.
involucre
the tubular or bilabiate indusium found in the Hymenophyllaceae and some Dennstaedtiaceae, in which the abaxial and adaxial portions are identical or nearly so.
involute
having the lateral margins rolled adaxially, thus exposing the abaxial surface and covering the adaxial surface. (ant. revolute).
iridescent
reflecting several rainbow-like colors, such as the rhizome scales of some Asplenium and Haplopteris species and the adaxial laminae of some Selaginella and Polypodiaceae.
isodiametric
approximately equal in length and width. (cf. elongate).
isodromous
with the basal pinnules and/or vein groups of the pinnae strictly opposite. (cf. anadromous, catadromous).
J
joint
see abscission, articulation, catenate.
jointed
see catenate, articulate, articulation, abscission.
L
laesura
the simple, elongate or triradiate, thickened or unthickened scar on the surface of pteridophyte spores. (pl. laesurae; syn. suture).
lamina
the expanded portion of a frond, usually consisting of a rachis or midrib, other axes or lateral veins, and expanded lamina tissue. (pl. laminae).
lanceate
spear-shaped, with a long, tapering apex and a nearly truncate base, therefore widest close to or at the base. (cf. lanceolate).
lanceolate
lance-shaped, with a long tapering apex and a short tapering base, therefore widest well above the base. (cf. lanceate).
latent bud
in the Gleicheniaceae and some Dennstaedtiaceae, a bud borne at the apex of an axis that is flanked by two branches; eventually it may break dormancy and elongate, most commonly extending the rachis of the frond. (cf. dormant bud).
lax
so weak as to be scarcely self-supporting.
lectotype
a specimen chosen by a later author to serve like a holotype from among the syntypes used and cited by the original author.
legitimate
a validly published name, and one that is not contrary to any article of the Code (ICBN). (ant. illegitimate; cf. correct, valid).
leptosporangia
plural of leptosporangium.
leptosporangiate
bearing leptosporangia, not eusporangia. (ant. eusporangiate)
leptosporangium
found only in ferns, a thin-walled, thin-pedicelled sporangium bearing usually 64 spores (128--512 in the Osmundaceae and 256 in the Schizaeaceae), and having an annulus. (pl. leptosporangium; adj. leptosporangiate; cf. eusporangium). Leptosporangia are found in all fern families except Equisetaceae, Marattiaceaee, Ophioglossaceae and Psilotaceae.
ligulate
(1) strap-shaped; parallel-sided with a more or less round apex. (cf. spathulate); (2) having a ligule.
ligule
a small, tongue-like, often triangular appendage located near the microphyll base (just distal to the sporangium on the adaxial surface of the microsporophyll); it is persistent in Isoëtes, but caducous in Selaginella. (adj. ligulate; adj.ant. eligulate).
linear
long, narrow, and of uniform or nearly uniform width.
lithophyte
see lithophytic (cf. epiphyte, epiphytic).
lithophytic
growing on rocks. (n. lithophyte; syn. epipetric, saxicolous).
lobate
having shallow sinuses that extend no more than half way from the lobe apex to the axis of the structure that bears the lobes. (n. lobe; syn. lobed; dim. lobulate; cf. pinnate, pinnatifid, pinnatisect).
lobe
a portion of a lamina, pinna, pinnule, or segment that is fully connate and with a shallow sinus on either side that extends no more than half way from the lobe apex to the axis that bears the lobe. (adj. lobate; dim. lobule; dim.adj. lobulate; cf. segment).
local
having a very restricted distribution, up to a few square kilometers.
long-creeping rhizome
a rhizome that grows horizontally for at least a few centimeters (usually many more) and that usually has distant stipe bases. (syn. long-repent rhizome; cf. short-creeping rhizome, rhizome).
longitudinal section
a section of an elongate structure, such as a rhizome or stipe, or a planate structure such as a lamina, that is parallel to the principal axis of the structure. If the section passes along and through the principal axis then it can also be called a radial section; if the section is to one side of the principal axis and therefore does not go through that axis then it can also be called a tangential section.
lustrous
reflecting light well because of a smooth surface. (syn. glossy, nitid, shiny; ant. matte).
lycophyte
see lycophytes.
lycophytes
a group of spore-bearing (seedless) vascular plants that, in terms of their reproductive biology, are similar to ferns but are not closely related to ferns. Lycophytes are the oldest extant group of vascular plants appearing some 50 million years before the first ferns. The group includes quillworts, clubmosses and spikemosses. (cf. monilophytes; fern-allies; pteridophytes).
M
marcescent
remaining attached long past maturity, but in a withered state. (cf. persistent).
marginal
pertaining to the margin; in sori, borne on the margin rather than on the surface. (ant. superficial; cf. costal, inframedial, intramarginal, medial, supramedial).
marginate
having the central cells of the body different in shape and orientation from the marginal ones. (cf. conform).
mature
incapable of further growth or maturation (especially in determinate structures). (cf. immature, senescent).
medial
(1) in the middle, midway between the base and apex. (cf. distal, proximal); (2) in the middle, in sori, borne midway between the costa or costule and the margin. (cf. costal, inframedial, intramarginal, marginal, supramedial).
megagametophyte
in heterosporous pteridophytes (Azolla, Isoëtes, Marsilea, Pilularia, Regnellidium, Salvinia, and Selaginella), a female gametophyte borne within a megasporangium and bearing one or more archegonia. (cf. microgametophyte).
megasporangia
plural of megasporangium.
megasporangium
in heterosporous pteridophytes (Azolla, Isoëtes, Marsilea, Pilularia, Regnellidium, Salvinia, and Selaginella), a sporangium bearing megaspores. (pl. megasporangia; cf. microsporangium).
megaspore
a large spore of the heterosporous pteridophytes (Azolla, Isoëtes, Marsilea, Pilularia, Regnellidium, Salvinia, and Selaginella) that produces a female gametophyte. (cf. microspore).
megasporocarp
a sporocarp that bears megasporangia.
megasporophyll
a fertile microphyll bearing or subtending a megasporangium. (cf. microsporophyll).
membranaceous
thin and very flexible. (cf. chartaceous, coriaceous, papyraceous).
meristem
a self-perpetuating, commonly tetrahedral cell or a region of cells that are thin-walled and mitotically dividing and that produce cells which will develop and differentiate into various tissues and structures.
microgametophyte
in heterosporous pteridophytes (Azolla, Isoëtes, Marsilea, Pilularia, Regnellidium, Salvinia, and Selaginella), a male gametophyte borne within a microsporangium and bearing one or more antheridia. (cf. megagametophyte).
microphyll
the photosynthetic organ of the lycophytes, always lacking a stipe, characterized by its usually minute size and unbranched vascular system (a single vein). (cf. frond, megaphyll).
microsporangia
plural of microsporangium.
microsporangium
in heterosporous pteridophytes (Azolla, Isoëtes, Marsilea, Pilularia, Regnellidium, Salvinia, and Selaginella), a sporangium bearing microspores. (pl. microsporangia; cf. megasporangium).
microspore
a small spore of the heterosporous pteridophytes (Azolla, Isoëtes, Marsilea, Pilularia, Regnellidium, Salvinia, and Selaginella) that produces a male garnetophyte. (cf. megaspore).
microsporocarp
a sporocarp that bears microsporangia.
microsporophyll
a fertile microphyll bearing or subtending a microsporangium. (cf. megasporophyll).
mixed sorus
see sorus.
moniliform
like a string of closely-set, round beads.
monilophyte
see monilophytes.
monilophytes
ferns. 9,000 - 12,000 species, including horsetails,whisk ferns, and all eusporangiate and leptosporangiateferns. (cf. lycophytes; fern-allies; pteridophytes).
monolete spore
a bilaterally symmetrical spore having a linear, unbranched laesura. (cf. alete spore, trilete spore).
monomorphic
having one shape, commonly applied to fertile versus sterile laminae or portions of laminae. (cf. dimorphic, hemidimorphic, polymorphic).
monophyletic
a group that shares (and includes) a common ancestor and all of its descendants. (syn. natural group; cf. artificial group, paraphyletic, polyphyletic).
mucilage
see mucilaginous.
mucilaginous
covered with a sticky and gelatinous exudate (such as the very young croziers of some species of Thelypteridaceae and Osmundaceae) or containing such a substance. (n. mucilage).
mucronate
bearing a short, stiff, bristle-like apical prolongation of a midrib, costa, costule or costulet. (n. mucro; dim. mucronulate; cf. apiculate, aristate, cuspidate).
mucronulate
diminutive of mucronate.
multicellular
formed of many cells. (syn. pluricellular; cf. bicellular, paucicellular, unicellular).
multiseriate
disposed in more than two rows; in scales, formed entirely or in part of more than two multicellular rows of cells. (cf. biseriate, uniseriate).
muricate
having very low, rather sharp protuberances, as the stipe bases of certain Cyatheaceae. (cf. aculeate, tuberculate).
muriform
bearing muri; a general term encompassing many more specialized terms. (n. murus; n.pl. muri; cf. bulliform, caviform, steliform).
murus
a general term for a narrow, elongate, wall-like protuberance; usually applied to spore ornamentation and the basis of many more specialized terms such as cristate, fossulate, pleurate, retate, reticulate, rivulate and rugate. (pl. muri; cf. bulla, cavus, stela).
myrmecophilous
inhabited or capable of being inhabited by ants, usually in modified rhizomes that provide food or shelter, as in Lecanopteris.
N
native
growing naturally, not as a result of introduction. (syn. indigenous; cf. exotic).
natural group
see monophyletic. (ant. artificial group)
naturalized
originally introduced, but now reproducing and spreading like a native species. (cf. adventive, escaped, introduced).
nectary
in ferns, a tissue, often a small patch or protuberance in the axil of a pinna, that is attractive and nourishing to ants that protect the plant, such as is found in Pteridium.
neotype
a specimen chosen by a later author to replace the holotype, lecototype, or syntypes when these and all their duplicates are missing or destroyed.
nerve
in pteridophytes, a simple or unbranched vein, often a terminal or ultimate vein. (cf. vein, veinlet, venuloid).
nidiform
forming a humus-collecting nest (generally of modified fronds), as in many species of Drynaria and Platycerium. (cf. calathiform).
node
(1) the point on a stem where leaves and branches are borne, especially in Equisetum, or the point on a rhizome where one or more fronds are borne; (2) a discoloured, swollen, or articulate area on the stem of some Selaginella or on the stipe of some ferns, especially Danaea; (3) the attachment points of the sheaths along the stems of Equisetum. (adj. nodose).
notched
having small transverse gaps; said especially of the ridges on the stems of some Equisetum species and of the cartilaginous margin of the laminae of some Selliguea species.
O
oblanceolate
gradually tapered toward the base with an obtuse or rounded apex; very narrowly obovate (cf. obovate).
oblique
(1) slanting at an angle to an axis or other structure; (2) unequal-sided, applied to the base or apex of a lamina, pinna or pinnule.
oblong
longer than wide with the long sides parallel or nearly so and the ends abrupt, rather than gradually tapered. (cf. quadrangular).
obovoid
a solid structure that is ovate in longitudinal section, with the narrower end basal. (cf. ovoid).
obsolete
reduced in size or length nearly to the point of elimination, applied especially to stipes. (cf. rudimentary, vestigial).
obtuse
forming an angle of 90° or more with the two sides straight or slightly convex. (cf. acuminate, acute, attenuate).
octoploid
a plant that has eight sets of chromosomes.
odorous
having an odor.
olivaceous
grayish yellow-green.
once-pinnate
see pinnate. (cf. bipinnate, tripinnate, quadripinnate).
opaque
not capable of transmitting light. (cf. translucent, transparent).
opposite
having two structures, in ferns usually pinnae, inserted opposite each other at a single point along an axis. (cf. alternate, verticillate).
order
a rank of taxa above family and below class; the totality of families that are more closely related to one another than they are to any other families of other orders. Sometimes a single, markedly distinct family also constitutes an order.
ovate
having the outline of a longitudinal section of a hen’s egg; similar to elliptical except broadest towards the base, rather than at the middle.
ovoid
a solid structure that is ovate in longitudinal outline, with the wider end basal. (cf. obovoid).
ovum
a non-motile, relatively large, female sex cell (gamete), produced in the archegonium. (pl. ova; syn. egg; cf. spermatozoid).
P
palea
see paleaceous. (pl. paleae).
paleaceous
bearing thin (in texture), flexible, basifixed or dorsifixed scales. (n. palea; n.pl. paleae; cf. aspidote, furfuraceous, squamous).
palmate
having four or more divisions radiating widely from a single point. (cf. digitate, pinnate, ternate).
papillate
(1) bearing minute, low, round protuberances. (n. papilla; n.pl. papillae); (2) a synonym of gemmulate, a specialized term used to describe the surface of spores that are covered with minute papillae. (cf. gemmulate).
papyraceous
having the texture and thickness of rather thin paper. (cf. chartaceous, coriaceous, membranaceous).
paraphyletic
an artificial group that excludes some of the descendants of its common ancestor. (cf. monophyletic, polyphyletic).
paraphysate
see paraphysis.
paraphyses
plural of paraphysis.
paraphysis
a minute, unicellular, paucicellular or multicellular (resembling a simple hair), usually elongate and often glandular structure borne on the soral receptacle, on the sporangium capsule or pedicel, or among the gametangia. (pl. paraphyses; adj. paraphysate; cf. gland, hair, sporangiaster).
paratype
a specimen cited in a protologue that is neither the holotype nor an isotype, nor one of the syntypes if two or more specimens were simultaneously designated as types.
parenchyma
a tissue formed of specialized, thin-walled, living cells with intercelluIar spaces, found in various places in plant bodies. (adj. parenchymatous; cf. sclerenchyma).
parenchymatous
see parenchyma.
paripinnate
pinnate and terminated by a pair of pinnae similar to the lateral ones. (ant. imparipinnate).
patellate
bearing bullae that are no higher than wide, greatly contracted at the base, and round to angular, plate-like, and often slightly concave. (cf. aculeate, colliculate, gemmulate, pustulate).
patent
directed strongly away from the surface of the structure on which it is borne. (cf. appressed, ascending, reflexed).
paucicellular
formed of a few cells. (cf. bicellular, multicellular, unicellular).
pectinate
comb-like; pinnatisect or very deeply pinnatifid with narrow, linear, close-set, segments.
pedate
having the basal basiscopic portions of the basal pinnae more developed and divided, sometimes repeatedly so, than the other portions of the laminae, as in certain Adiantum and Pteris species.
pedicel
(1) the stalk of a sporangium. (cf. capsule, petiolule); (2) the basal cell or cells of a stellate hair or the stalk of a peltate scale or peltate indusium. (syn. stalk; cf. arm, ray).
pedicellate
having a pedicel; usually applied to sporangia, stellate hairs and peltate scales. (syn. pedicelled, stalked; ant. sessile; cf. petiolulate).
pedicelled
see pedicellate.
peduncle
in Marsilea, the stalk of the sporocarp. (adj. pedunculate)
pedunculate
having a peduncle.
peltate
attached by a central pedicel, applied to certain indusia and scales and to the sporangiophores of Equisetum. (cf. basifixed, dorsifixed; cf. pseudopeltate).
pentagonal
5-angled, and so 5-sided, as the lamina outline in some species of Davallia and Cheilanthes. (cf. quadrangular, triangular).
pentaploid
a plant that has five sets of chromosomes.
penultimate
one before the last in a series; between the antepenultimate and last in a series. (cf. antepenultimate).
perispore
the often highly ornamented, outer, sporopollenin layer of the spore wall that is deposited on the exospore by the disintegrating tapetum during spore formation. (syn. perine; cf. endospore, epispore, exospore).
persistent
remaining attached long past maturity in good condition. (cf. caducous, deciduous, marcescent).
petiolulate
having a petiolule; i.e. having a free, usually short portion of the costa, costule or costulet at the base of the pinna, pinnule, or pinnulet that attaches to the axis of the next higher order. (syn. stalked; ant. sessile; cf. pedicellate, stipitate).
petiolule
the short, free, basal portion of a costa, costule, or costulet. (syn. stalk, stipicel; cf. petiole, pedicel, sessile).
phloem
the vascular tissue specialized for transporting photosynthetic products through the plant. (cf. xylem).
phyllopodia
plural of phyllopodium.
phyllopodium
in ferns with articulate stipes, that portion of the stipe proximal to the articulation that remains attached to the rhizome. Phyllopodia are especially prominent in Elaphoglossum and Oleandra but are low and knob-like in Adiantum and many Polypodiaceae. (pl. phyllopodia)
pinna
a primary division of a compound lamina; a pinna may be petiolulate, sessile or (in pinnatisect fronds) adnate to the rachis. (pl. pinnae; cf. pinnule, pinnulet).
pinna-rachis
see costa.
pinnate
(1) having pinnae that are entire or lobed less than half way to the costae (cf. bipinnate, tripinnate, quadripinnate, lobate, pinnatifid, pinnatisect); (2) having two or more pinnae on each side of a rachis that are not borne from a single point (cf. ternate); (3) branching in which a major free vein gives rise to minor, lateral, free veins.
pinnatifid
incised nearly all the way to the axis (or, ar least, more than half way to the axis), with the segments still partially attached, laterally, to neighbouring segments. (cf. lobate, pinnate, pinnatisect).
pinnatisect
incised all the way to the axis with the segments not contracted at their base and therefore adnate on the axis. (cf. lobate, pinnate, pinnatifid).
pinnule
a petiolulate or sessile division of a pinna that has no lateral attachment to neighbouring divisions. (cf. pinna, pinnulet).
pinnulet
a petiolulate or sessile division of a pinnule that has no lateral attachment to neighbouring divisions. (cf. pinna, pinnule).
pleurate
bearing muri that are long, low, and parallel, and that have sulci between them that are as wide as the muri. (cf. fossulate, rivulate).
polymorphic
having several forms. (cf. dimorphic, hemidimorphic, monomorphic).
polyphyletic
an artificial group that excludes a common ancestor. (cf. monophyletic, paraphyletic).
polyploid
a plant that has more than two sets of chromosomes in cells of the sporophyte or more than one set in cells of the gametophyte.
primary
the first or principal order; applied especially to the veins or axes in a branching system. eg. the main lateral veins arising from the midrib in a simple lamina (as in many Polypodiaceae) or the first lateral branches from the rachis in Gleicheniaceae. (cf. secondary, tertiary, quaternary, quinary).
procumbent
lying on the substrate, but not rooting. (cf. decumbent, prostrate, sarmentose).
produced
more greatly developed than is usual, applied especially to auricles or other parts of laminae or other plane structures. (ant. reduced; cf. prolonged).
proliferous
forming bulbils or plantlets on the laminae, the latter commonly in the axils of distal pinnae, as in Tectaria, or occasionally along the lamina margin, as in Asplenium. (cf. radicant).
prominent
noticeable because of contrasting colour and/or raised position with respect to surrounding tissue.
prominulous
slightly raised above the lamina tissue, and so readily seen upon cursory examination, applied to midribs, costae and veins. (cf. complanate, immersed, impressed, superficial).
prostrate
lying on the substrate (a general term). (cf. decumbent, procumbent, sarmentose).
prothallus
see gametophyte.
protologue
all the elements associated with a name at its original publication: the description or diagnosis, illustration(s), synonymy and references, specimens cited, and other notes and comments.
protuberance
a structure that bulges or swells out.
proximal
towards or near the base. (cf. basiscopic, distal, medial).
pruinose
having the surface obscured by a rather thick, bluish or whitish, wax-like coating, such as the rhizomes of some Arthromeris and Goniophlebium species. (cf. farinose, glaucous).
pseudodichotomous
not dichotomous but appearing, on cursory examination, to be dichotomous, applied especially to frond complexity and venation. eg. the branching of the fronds of Gleicheniaceae, which bear a latent bud or a dormant bud in each apparent dichotomy; the helicoid branching pattern of some Adiantum species; or a pattern of venation in which the two veins resulting from each fork are free and unequal. (n. pseudodichotomy; syn. falsely dichotomous; cf. dichotomous, pinnate)
pseudoindusia
plural of pseudoindusium.
pseudoindusium
an introrse, reflexed or revolute, often modified lamina margin that protects young sporangia, especially in the Adiantaceae. (syn. false indusium; cf. coenoindusium, indusium).
pseudopeltate
basifixed with large, overlapping auricles, and so appearing to be peltate, as in the rhizome scales of some Polypodiaceae. (cf. peltate).
pteridologist
a specialist in pteridology, the study of pteridophytes in a broad sense that includes the ferns (monilophytes) and the more distantly related lycophytes.
pteridology
the study of pteridophytes in a broad sense that includes the ferns (monilophytes) and the more distantly related lycophytes.
pteridophyta
the taxonomic group (Division) that contains all the vascular plants that bear spores instead of seeds: i.e. monilophytes (ferns, now including horsetails and whisk ferns) and lycophytes (quilllworts, clubmosses and spikemosses). In some classifications Pteridophyta is considered a subdivision of Tracheophyta (the Division that contains all vascular plants). (syn. Pteridophytes, "Ferns & Fern Allies").
pteridophytes
in modern usage, a synonym of ferns. In traditional usage, the term was the equivalent of Pteridophyta (or “ferns and fern-allies”) and therefore referred to all the vascular plants that bear spores instead of seeds. i.e. ferns, horsetails and whisk ferns (now all regarded as true ferns) and quillworts, clubmosses and spikemosses.
puberulent
diminutive of pubescent.
pubescent
downy; bearing simple or branched, short, erect, soft hairs. (dim. puberulent; cf. puberulous).
pubigerous
see pubescent.
pulvinus
in the Marattiales, a swollen, node-like region at the base of a stipe or costa that loses or gains turgidity under different conditions of hydration and consequently causes fronds or pinnae to collapse or regain their normal position.
Q
quadrangular
4-angled, and so 4-sided. (cf. oblong, pentagonal, triangular).
quadrifid
divided into four similar parts, but not nearly to the base. (cf. bifid, bipartite; quadripartite).
quadripartite
divided into four similar parts to or nearly to the base, such as the fronds of Marsilea. (cf. bifid, bipartite, quadrifid).
quadripinnate
divided into pinnae bearing pinnules with the pinnules themselves bipinnate. (syn. 4-pinnate; cf. bipinnate, pinnate, tripinnate).
quadripinnatifid
tripinnate with the secondary pinnules pinnatifid. (syn. tripinnate-pinnatifid).
quadripinnatisect
quadripinnate with the pinnulets pinnatisect. (syn. tripinnate-pinnatisect).
quaternary
the next order after tertiary, applied especially to the veins or axes in a branching system. (cf. primary, secondary, tertiary, quinary).
quinary
the next order after quaternary, applied especially to the veins or axes in a branching system. (cf. primary, secondary, tertiary, quaternary).
R
rachis
the principal, central axis of a pinnatifid or more compound lamina (cf. midrib, the principal central axis of a simple or lobate frond).
radial
radiating from a central point.
receptacle
the point or region of the lamina tissue, often thickened and supplied by one or more veins, that produces sporangia and sometimes paraphyses and/or sporangiasters.
recumbent
growing loosely over other vegetation, especially shrubs. (syn. scrambling; cf. scandent).
recurrent
running or pointing towards the midrib or point of origin, usually applied to veins. (cf. excurrent).
reduced
simplified or smaller than is usual. (syn. abbreviated; ant. produced).
reflexed
obliquely directed away from a surface and towards the base of the structure on which it is borne. (syn. deflexed; cf. appressed, ascending, patent).
reniform
kidney-shaped; shallowly crescent-shaped with rounded ends, applied to certain indusia and spores. Note, however, that this term is often loosely applied and that, in fact, most "reniform" indusia are not kidney-shaped. "Reniform" indusia may be almost circular with a shallow notch/short attachment point (i.e. round-reniform) or may be more horseshoe-shaped with a deeper notch/longer attachment point (i.e. elongate-reniform or hippocrepiform). "Reniform" spores may be kidney-shaped but many would be more accurately described as bean-shaped (fabaeform).
repent
extending horizontally in or on the soil and rooting throughout, often producing a line of fronds. (syn. reptant; cf. ascending, erect).
retate
bearing muri that are wide and rounded, freely anastomosing, and form short, broad areolae. (syn. rugulate; cf. cristate, reticulate, rugate).
reticula
plural of reticulum. See reticulate.
reticulate
having a branching pattern in the form of a mesh-like or lattice-like net-work. (n. reticulum; n.pl. reticula).
reticulum
see reticulate. (n.pl. reticula; adj. reticulate).
retuse
having a narrow, V-shaped sinus at the round or obtuse apex of a segment, lobe, or tooth. (cf. emarginate).
revolute
having the lateral margins rolled abaxially, thus exposing the adaxial surface and covering the abaxial surface. (ant. involute).
rheophyte
see rheophytic.
rheophytic
growing in a location that is frequently but not permanently exposed to fast running water, such as on or between rocks along riverbanks or on islands in rivers. (n. rheophyte; cf. amphibious, aquatic, terrestrial )
rhizoid
an elongate, non-vascularized, unicellular or paucicellular structure that serves to anchor the gametophyte and to absorb water and nutrients from the substrate. (cf. root, root hair).
rhizome
in ferns, a usually short (compared to the fronds), scaly or hairy (rarely glandular or glabrous) anchorage structure that bears roots and fronds. Rhizomes may be erect or ascending (and, in either of these cases, trunk-like or not; -- see caudex) or they may be creeping (repent) or climbing (scandent). Creeping rhizomes are often further described as short-creeping (short-repent) or long-creeping (long-repent). (cf. stem).
rhombiform
having the form of a parallelogram, often somewhat to much longer than wide.
rivulate
bearing muri that are long, low, and parallel, with the sulci between them wider than the muri, as in Ceratopteris. (syn. ribbed; cf. fossulate, pleurate).
root
an elongate, vascularized, multicellular structure that serves to anchor the sporophyte and to absorb water and nutrients from the substrate. (adj. rooted; cf. root hair, rhizoid).
root hair
a generally elongate, unicellular, non-vascular outgrowth of a cell of the epidermis of roots that serves to absorb water and nutrients from the substrate. (cf. rhizoid, root).
rosulate
having a circular, radiating cluster of fronds borne horizontally at ground level from a largely subterranean rhizome. (n. rosette).
round
circular in outline (syn. orbiculate; cf. rounded).
rounded
broadly curved to semicircular in outline; usually applied to the shape of an apex or base or the underside of a stipe. (cf. round, circular, orbiculate).
round-reniform
a reniform indusium that is almost circular, compared to a reniform indusium that is more elongate (or horse-shoe shaped). (cf. elongate-reniform).
rudiment*
{definition coming soon}
rugate
bearing muri that are wide, rounded, and non-anastomosing and that do not form areolae. (syn. wrinkled; cf. cristate, retate, reticulate).
S
saccate
bearing stelae that are higher than wide, bulbous, apparently deflated and collapsed, and widest at the middle. (cf. baculate, clavate, echinate, tuberculate, verrucate).
sagittate
having the shape of an arrowhead with basiscopically directed basal lobes. (cf. cordate, hastate).
sarmentose
arching above the soil and rooting at intervals, as the rhizomes of certain Lycopodiella and Oleandra species. (cf. decumbent, procumbent; prostrate).
sarmentum
a very thin, recumbent or prostrate root-like or stem-like structure that lacks small, leaf-like appendages but forms new plants along its length or at its tip, as in Nephrolepis. (pl. sarmenta; cf. stolon).
saxicolous
see lithophytic.
scale
in ferns, a multicellular, usually plane, lanceate or lanceolate to circular, basifixed, dorsifixed, or peltately attached epidermal outgrowth a few to typically many cells wide at the base, but often one cell wide or even hair-like at the apex. Scales are particularly numerous at and near the apices of rhizomes, on the basal parts of stipes and on croziers but they are also found on the laminae of many species. Scale characters are extremely important for fern identification and classification. (adj. scaly; cf. bristle, squamule).
scandent
climbing closely on other vegetation, especially tree trunks, as the rhizomes of Stenochlaena (syn. climbing; cf. recumbent).
sclerenchyma
a tissue of very thick-walled cells specialized for support that are dead at maturity, usually associated with vascular tissue in axes or laminae. (adj. sclerenchymatous; cf. parenchyma).
sclerotic
hard or stony.
scrambling
see recumbent.
secondary
the next order after primary; applied especially to the veins or axes in a branching system. eg. secondary veins are the smaller veins or vein-groups that arise from the primary veins, especially the transverse veins linking adjacent primary veins of a simple lamina, as in many Polypodiaceae. (cf. primary, tertiary, quaternary, quinary, transverse).
segment
a portion of a lamina, pinna, or pinnule that is fully adnate and with a deep sinus on each side that extends more than half way from the segment apex to the axis that bears the segment. (cf. lobe).
senescence
the ageing of a plant or part of a plant after maturity, leading eventually to its death. Senescence of fronds or pinnae often, but not always, leads to their abscission.
senescent
grown old; exhibiting changes in biology as a result of ageing after maturity. (cf. immature, mature).
septate
provided with or divided by septa; in hairs, having thickened and obvious transverse walls between the cells. (n. septum; n.pl. septa; ant. aseptate).
septum
a partition or cross-wall in certain kinds of hairs or hair-like structures. (pl. septa; adj. septate; adj.ant. aseptate).
seriate
disposed in series or rows, applied to a group of similar structures so arranged. (n. series).
serrate
having usually broad teeth on the margin directed acroscopically. (dim. serrulate; cf. crenate, dentate).
serrulate
diminutive of serrate. (cf. crenulate, denticulate).
sessile
lacking a free, basal portion of a stipe, costa, costule or costulet; also applied to organs and structures that lack a pedicel or foot. (ant. pedicellate, petiolulate, stipitate).
seta
a stiff, usually straight, terete, and often dark-coloured hair, found especially on the stipes and laminae of some Grammitidaceae. (cf. cilium)
setiform
having the form of a seta, a stiff, usually straight, terete, and often dark-coloured hair, found especially on the stipes and laminae of some Grammitidaceae. (n. seta; n.pl. setae; cf. ciliform).
setose
bearing stiff, thin, straight hairs, as on the laminae and stipes of many species or as on the sporangia of some Grammitidaceae and Thelypteridaceae (dim. setulose; cf. ciliate, cincinnate).
sheath
a tubular structure composed of laterally connate leaves that closely and completely or partially surround a stem, as in Equisetum.
short-creeping rhizome
a rhizome that grows horizontally for a few centimeters at most and that usually has approximate stipe bases. (syn. short-repent rhizome; cf. long-creeping rhizome, rhizome).
shrivelled
curled and wrinkled because of tissue collapse and the loss of moisture, often with age.
simple
not divided, nor compound, nor branched; in laminae, without segments or pinnae; in pinnae, without pinnules. (cf. compound, decompound).
skeletonized
having expanded lamina tissue reduced or absent; characteristic of Psilotum, some Hymenophyllaceae and Schizaeaceae, the fertile pinnae of some strongly dimorphic species and the aphlebiae of some species of Cyatheaceae.
solitary
single, and so not near another similar structure.
sorophore
the gelatinous, sporangium-bearing ring produced by the sporocarp of Marsileaceae during germination.
sorus
a cluster of sporangia having a distinct shape. Maturation of the sporangia may be simple (simultaneous), gradate (sequential), or mixed (a combination of the two foregoing types). (pl. sori; adj. soral).
spathulate
spatula-shaped; narrow at the base and gradually wider distally to a rounded apex. (cf. ligulate).
species
a rank of taxa grouping individuals that typically have a distinct cytology, genetic composition, morphology, and range.
sperm
see spermatozoid.
spermatozoid
a motile, relatively small, male sex cell (gamete) produced in the antheridium. (syn. antherozoid, sperm; cf. ovum).
spherical
having the shape of a sphere.
spicular cell
a needle-like, rather thick-walled, idioblast in the epidermis of the lamina, especially in Adiantum and the Vittariaceae. (cf. idioblast).
spine
a hard, elongate, sharp-pointed projection, found especially in certain species of Cyatheaceae, Dennstaedtiaceae, and Marattiaceae. Corticinate spines arise from the cortex; squaminate spines are the thickened, central portion of an elongate scale at maturity with the thin marginal portion worn away. (adj. spiny; adj.dim. spinulose; n.dim. spinule).
spinulose
diminutive of spiny; bearing epidermal projections in the form of short, spine-like teeth along the lamina margin, as the pinnules of most species of Polystichum. (n. spinule).
sporangia
plural of sporangium.
sporangiaster
an abortive, modified, non-spore-bearing sporangium that presumably serves, like a paraphysis, to protect developing sporangia. (cf. paraphysis).
sporangiophore
a greatly transformed, peltate sporophyll bearing a ring of approximately six sporangia facing the axis of the strobilus of Equisetum. (cf. sporophore).
sporangium
the spore-producing structure of pteridophyta. (pl. sporangia). Sporangia are categorized based on their developmental biology into eusporangia and leptosporangia.
spore
a unicellular, commonly spherical, tetrahedral, reniform or bean-shaped, often elaborately ornamented reproductive structure produced within the sporangium that germinates to form a gametophyte.
sporocarp
in Marsilea, the hard, short- to long-pedunculate, nut-like structure containing the sporangia, apparently a highly modified leaf or leaflet; in Azolla and Salvinia, a thin, short-pedicelled, globular structure containing the sporangia, apparently a modified indusium. (syn. rhizocarp).
sporophore
in pteridophytes, the fertile portions of a hemidimorphic frond, as in the Ophioglossaceae (cf. sporangiophore, trophophore).
sporophyll
(1) in ferns, a frond bearing sporangia; (2) in most lycophytes, a scale-like microphyll subtending a sporangium; (3) in Isoëtes, an elongate microphyll bearing a sporangium within its base. (ant. trophophyll); (4) in Equisetum …? {definition under revision}
sporophyte
in pteridophytes, the conspicuous plant that produces spores. (cf. gametophyte).
spreading
diverging ever more strongly in different directions, and so greatly separated distally one from another, as the labia of the involucres of some Hymenophyllaceae or the scales on some rhizomes and stipes. (syn. flared; cf. divaricate, divergent).
squamose
bearing thick (in texture), stiff, basifixed or dorsifixed scales. (n. squama; n.pl. squamae; dim. squamulose; cf. aspidote, furfuraceous, paleaceous).
squamule
a minute, reduced, paucicellular scale, found especially on the axes and/or laminae of certain Cyatheaceae. (cf. bristle, scale).
stalked
having a stalk; a general term encompassing many more precise terms such as petiolate, petiolulate, pedicellate, pedicelled, pedunculate, stipitate.
stela
a general term for a radially symmetrical more or less rod-like protuberance (hence higher than wide); usually applied to spore ornamentation and the basis of many more specialized terms such as baculate, clavate, echinate, saccate, tuberculate and verrucate. (pl. stelae; cf. bulla, cavus, murus).
stele
the vascular tissue (i.e. one or more vascular bundles composed of xylem and phloem) and associated tisues of a rhizome or other type of stem.
steliform
bearing stelae; a general term encompassing many more specialized terms. (n. stela; n.pl. stelae; cf. bulliform, caviform, muriform).
stellate
star-shaped; applied to hairs and scales. Simple stellate hairs are branched above the base (from the apex of the pedicel) into three or more usually equal rays (see, for example, the hairs on the lamina of Pyrrosia, Platycerium and some Grammitidaceae). Twice-stellate hairs are forked or branched above the base (from the apex of the pedicel) into two or more arms, with each arm branching into three or more usually equal rays (see, for example, the hairs on the stipes and laminae of some Hymenophyllaceae); Stellate scales bear several broad to narrow teeth, usually of unequal size, from a relatively large central point (see, for example, the scales on the lamina of some Asplenium species). (cf. bifurcate, twice-bifurcate).
stem
in lycophytes, a usually long (compared to the microphylls), glabrous (rarely hairy) anchorage structure that bears roots and microphylls. (cf. rhizome).
sterile
in relation to sporophytes: lacking sporangia or viable spores; in relation to gametophytes: lacking gametes and/or gametangia. (ant. fertile).
stipe
the structure of a frond that connects the base of the lamina to the point of its attachment to the rhizome. (syn. petiole).
stipitate
having a stipe. (syn. petiolate; ant. exstipitate; cf. petiolulate).
stipule
(1) in the Marattiaceae, each one of a pair of lateral, fleshy, starch-bearing, persistent, partially or entirely vascularized outgrowths of the rhizome that clasp the base of the stipe and that are capable of reproducing the plants vegetatively; (2) in the Ophioglossaceae, merely the remnants of the older stipe base that originally enclosed and protected the younger, less developed fronds.
stolon
a very thin, recumbent or prostrate root-like or stem-like structure that bears small, leaf-like appendages and forms new plants along its length or at its tip, as in Selaginella. (syn. sobol; cf. sarmentum).
stoma
a minute, epidermal pore bordered by a pair of relatively large and conspicuous (under the microscope) guard cells and often a usually uniform array of subsidiary cells that differ from the adjacent epidermal cells. (pl. stomata; syn. stomate).
stramineous
the colour of old straw.
strigose
bearing short, usually fully appressed, straight, coarse and sharp-pointed hairs. (dim. strigulose).
strigulose
diminutive of strigose.
strobilus
in lycophytes and Equisetum, a compact reproductive structure borne at the tips of branches or axes consisting of a central axis bearing closely spaced, spirally arranged sporophylls (in lycophytes) or sporangiophores (in Equisetum). (syn. cone).
subspecies
a rank of taxa subordinate to species and used for major variants in morphology (such as “incipient species”) that have a discrete range different from that of the species and any other subspecies.
subtending
see subtended.
subtropical
growing north or south of the tropics in regions with a hot summer and a warm to cool winter (ca. 23°30’–34° N or S Lat.).
sulcate
having one or more longitudinal grooves, especially on the adaxial side of a stipe, rachis, or costa. (n. sulcus; pl. sulci; cf. bisulcate, canaliculate, trisulcate).
sulcus
a longitudinal groove, especially on the adaxial side of a stipe, rachis, or costa. (pl. sulci; adj. sulcate).
superficial
on the surface of the lamina, rather than on the margin, applied especially to sorus position (ant. marginal; cf. complanate, immersed, impressed, prominulous).
supramedial
distal to the middle, applied to sori that are a little farther from the costa or costule than the margin. (cf. costal, inframedial, intramarginal, marginal, medial).
surcurrent
extending acroscopically on and adnate to an axis. (cf. decurrent, sursumcurrent).
sursumcurrent
extending both acroscopically and basiscopically on and adnate to an axis. (cf. decurrent, surcurrent).
symmetric
having a similar outline on both sides of a central axis. (ant. asymmetric).
synangium
a group of sporangia partially to entirely fused laterally, as in Psilotum and some Marattiales. (pl. synangia; cf. coenosorus).
synonym
one of two or more names for the same taxon; if based on the same type (homotypic), they are considered to be nomenclatural synonyms; if based on different types (heterotypic), they are considered to be taxonomic synonyms.
syntype
any one of two or more specimens used and cited by the author to prepare the diagnosis or description, when no holotype was designated. One of the syntypes may be selected to be a lectotype by a later author, but the “rejected” syntypes do not become paratypes, they remain syntypes.
T
tapered
see decrescent, angustate.
tapetum
the nutritive tissue of the sporangium capsule external to the spores.
temperate
growing in regions (or climates) with a warm summer and cold winter (ca. 34°–58° N or S Lat.).
terete
circular in cross-section, said especially of cylindrical bodies like axes, especially stipes.
terminal
at or pertaining to the apex or tip, commonly applied to simple structures like hairs, scales, or paraphyses. (cf. apical, lateral).
ternate
having three equal or subequal parts borne from a single point at about right angles or nearly so to each other. (cf. digitate, palmate, pinnate).
terrestrial
growing in soil. (cf. aquatic, amphibious).
tertiary
the next order after secondary; applied especially to the veins or axes in a branching system. eg. tertiary veins are the smaller veins that arise from secondary veins. (cf. primary, secondary, quaternary, quinary).
tetrahedral
having the shape of a pyramid with a triangular base, applied to spores.
tetraploid
a plant that has four sets of chromosomes.
thalloid
composed of a flat tissue, and multicellular in two or three dimensions, said of most gametophytes. (ant. filamentous).
toothed
having narrowly triangular projections from the margin of a structure. (cf. dentate).
translucent
sufficiently clear to pass light, but not an image. (syn. diaphanous; cf. opaque, transparent).
transparent
sufficiently clear to pass an image. (syn. diaphanous; cf. opaque, translucent).
transverse
(1) a section of an elongate structure, such as a rhizome or stipe, or a planate structure, such as a lamina, that is at a right angle to the principal axis of the structure. (syn. cross-section; cf. longitudinal section); (2) running perpendicularly between a pair of veins of a higher order, applied to veins and venuloids. (syn. cross-vein; cf. secondary).
transverse section
see transverse. (cf. longitudinal section).
trapeziform
having the outline of a trapezium, with four unequal sides, none of them parallel.
triangular
3-angled, and so 3-sided, as the laminae of certain Adiantum and Lindsaea species. (cf. pentagonal, quadrangular, trigonal, triquete).
trigonal
triangular in transverse section, with three angles and three convex or concave sides (cf. triangular, triquete).
trilete spore
a radially symmetrical (spherical or tetrahedral) spore having a laesura with three radiating branches. (cf. alete spore, monolete spore).
tripartite
divided into three parts.
tripinnate
divided into pinnae bearing pinnules with the pinnules themselves pinnate. (syn. 3-pinnate; cf. bipinnate, pinnate, quadripinnate).
tripinnatifid
bipinnate with the pinnules pinnatifid. (syn. bipinnate-pinnatifid).
tripinnatisect
bipinnate with the pinnules pinnatisect. (syn. bipinnate-pinnatisect).
triploid
a plant that has three sets of chromosomes.
triquete
triangular in transverse section, with three angles and three plane sides (cf. triangular, trigonal).
trisulcate
having three longitudinal grooves, especially on the adaxial side of the stipe, rachis, or costa. (cf. bisulcate, sulcate).
trophophore
the sterile portion of a hemidimorphic frond, as in the Ophioglossaceae. (cf. sporophore).
trophophyll
a vegetative, nutrient-producing frond or microphyll. (ant. sporophyll).
trophopod
the enlarged, persistent, basal portion of a stipe that functions as a storage organ, especially through the cold months, found in some ferns of temperate regions.
tropical
growing in regions with a hot summer and a warm to hot winter (ca. 0°–23°30’ N or S Lat.).
tuber
an often scaly, globular to somewhat elongate storage body usually borne on the rhizome or on stolons and sarmenta of a few species of pteridophytes in genera such as Lycopodiella, Selaginella, and Nephrolepis.
tuberculate
(1) bearing stelae that are more than 1 x and less than 1.5 x longer than wide, regular in form (knob-like), and have a rarely truncate or an obtuse to round apex (protuberance). (cf. baculate, clavate, echinate, saccate, verrucate); (2) having short, rounded protuberances, as the stipe bases of certain Cyatheaceae. (cf. aculeate, muricate).
twice-bifurcate
applied to hairs that branch dichotomously twice. i.e. forked above the base (from the apex of the pedicel) into two arms, with each arm forked into two equal or subequal rays. (cf. bifurcate, stellate, twice-stellate).
twice-pinnate
see bipinnate. (cf. pinnate, tripinnate, quadripinnate).
U
ultimate
the last or smallest order or division. (cf. antepenultimate, penultimate).
uniauriculate
bearing one auricle. (cf. biauriculate).
unicellular
formed of a single cell. (cf. bicellular, multicellular, paucicellular).
unilateral
missing from or different on one side of an axis compared to the other side. (cf. bilateral).
uniseriate
disposed in one row. (cf. biseriate, multiseriate).
V
valid
a name that is published in accordance with the articles of the Code (ICBN) governing publication; basically one that is effectively published, in the correct form for its rank, with a description or diagnosis or reference to a previously published description or diagnosis, and states a type. (ant. invalid. cf. correct, legitimate).
valve
(1) an involucral lobe, especially in Hymenophyllum and some Dennstaedtiaceae; (2) each half of a sporangium that is divided into halves, as in the Osmundaceae.
variety
a rank of taxa subordinate to species and used for variants in morphology that have a distinct range commonly different from that of the species and from other varieties of the species.
vascular bundle
an elongate strand of conducting cells (xylem tracheids and phloem sieve cells) that serve to conduct water, mineral nutrients, and photosynthetic products. (cf. stele, vascular tissue, vein).
vein
a strand of vascular tissue, especially one in the lamina. (cf. nerve, vascular bundle; veinlet, venuloid).
ventral
the lower side of a horizontal axis, such as a creeping rhizome, or of a plane non-vascular structure, such as a gametophyte. (ant. dorsal; cf. abaxial).
venuloid
an elongate series of thickened cells appearing to be a vein, but not connected to true veins and not functioning as a vein; found in the laminae of certain Selaginellaceae, Marattiaceae, Adiantaceae and Hymenophyllaceae. (syn. false vein; cf. nerve, vein, veinlet).
vernation
the manner in which the apices of laminae and their subdivisions uncoil or unfold during development to protect their apical meristems.
verrucate
bearing stelae that are more than 1 x and less than 1.5 x longer than wide, irregular in form (wart-like), and have a rarely truncate or an obtuse to round apex (protuberance). (syn. papillose; cf. baculate, clavate, echinate, saccate, tuberculate).
verticil
see verticillate. (syn. whorl).
verticillate
having three or more similar structures inserted at a single point along an axis. (n. verticil; syn. whorled; cf. alternate, opposite).
vestigial
occurring in reduced form, compared with a more developed form in related or ancestral species. (cf. obsolete; rudimentary).
viviparous
see bulbiferous.
W
whisk-fern
{definition coming soon}
whorl
see verticillate. (syn. verticil).
whorled
see verticillate. (syn. verticillate).
X
xerophyte
see xerophytic.
xerophytic
growing in dry places. (n. xerophyte).
xylem
the vascular tissue specialized for the transport of water and minerals throughout the plant. (cf. phloem).
Z
zigzag
see zigzagging.
zigzagging
a line, course, or axis that has a series of sharp turns going repeatedly from one direction to another. (n. zigzag).
zygote
a cell formed by the union of a spermatozoid and an ovum, and so the first cell (generally diploid, except in polyploids) of the sporophyte.
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