Flora of Bhutan Umbelliferae: Acronema

Acronema Edgeworth Mark F. Watson

Slender to robust, largely glabrous perennial herbs, roots tuberous or rhizomatous. Leaves biternate or pinnately divided; upper cauline leaves often with narrower segments than those below, glabrous or only the veins above or margins with hairs, often paler below; base of petiole narrowly sheathing the stem. Umbels compound, bracts and bracteoles absent or few, linear or lanceolate, often falling early; umbellules small. Calyx teeth obsolete. Petals ovate to lanceolate with a characteristic acute to acuminate or filiform apex. Stylopodium usually flattened or domed; styles erect to spreading. Fruit narrowly ovoid or sub-globbose and abruptly narrowed at apex, mericarps thinly 5-ribbed.

Note: A critical genus of the Sino-Himalayan region, with several erroneous records based on misidentifications; literature records for A. handellii H.Wolff, A. muscicolum (Handel-Mazzetti) Handel-Mazzetti and A. paniculatum (Franchet) H.Wolff have not been substantiated. For blunter-petaled specimens compare with Sinocarum, which is often characterised by expanded petiole sheaths, a stouter rhizome and somewhat irregular flowers.

Key to species

1	Rootstock a thick elongate rhizome or tap-root; umbels usually many-rayed, rays >8; umbellules many-flowered, pedicels, >9, minutely puberulent; petals elliptic to obovate, apex acute	*A. bellum*
+	Rootstock a globose tuber or slender rhizome; umbels with fewer (<8) rays, and fewer pedicels (<8) both usually glabrous; petals ovate-acuminate to lanceolate with a filiform tip	2

2	Leaflets with margin, main and secondary veins conspicuously scaberulous above; petals ovate (>0.7mm wide) with an acuminate tip; fruit subglobose	*A. nervosum*
+	Leaflets glabrous or minutely scaberuolous on margins and midrib only, petals lanceolate (<0.7mm wide) tips acuminate to filiform; fruit narrowly ovoid or subglobose	3

3	Plants usually >25cm tall; petals creamy white with long densely pubescent filiform tips 2–3 x length of blade; mature fruits subglobose	*A. hookeri*
+	Plants usually <25cm tall; petals white to purplish, acute to acuminate, but tips <2 x blade and at most minutely pappilate; fruits subglobose to narrowly ovoid	4

4	Plants usually <5cm tall; petals linear-subulate; fruit sub-globbose	*A. sichuanense*
+	Plants >5cm tall; petals lanceolate; fruit ovoid-globbose to narrowly ovoid	5

5	Petals purplish with narrowly acuminate or shortly filiform minutely papillate tips; fruits narrowly ovoid	*A. tenerum*
+	Petals acute, glabrous; fruits ovoid-globose	*A. pseudotenerum*

Acronema bellum (C.B.Clarke) P.K.Mukherjee

Pimpinella bella C.B.Clarke

Stems 15–60(–90)cm tall, erect from a thickened tap-root or elongate rhizome; rhizome 1.5–3.5 x 0.6–1.5cm. Leaves often both tufted at the base and cauline, pinnate, whitish or pale beneath, glabrous; lower leaves 6–25(–50) x 3–8(–13)cm (including petiole), sheathing base c 3mm broad (to 6mm in upper leaves); leaflets 0.5–5(–15) x 0.5–1.7(–3)cm, again pinnate, pinnatisect or ternately divided into oblong–rounded segments; segments 3–7mm wide in lower leaves, margins serrate in apical half. Umbels terminal and lateral, 8–16-rayed, (2.5–)4–7(–13)cm across; rays elongating in fruit, 2.5–6cm; bracts absent or solitary, c 2.5cm, linear-lancolate; umbellules 8–19-flowered, 1–2cm across; pedicels (4–)6–10mm, minutely pappilose puberulent; bracteoles 0–5, linear c 6mm. Petals white, 1.5–2.5 x 0.6–1mm, elliptic to obovate, apex acute, distinctly clawed at base. Stylopodium purple-brown somewhat domed, styles erect to divergent. Fruit 2–3 x 0.75–1mm, narrowly ovoid.

Bhutan: C—Thimphu district (Daga La, Hongstu, Talukah La to Ginnekah, Thimphu); N—Upper Mo Chu district (Gangyuel).
Sikkim: Bikbari, Kongra La, Lachen, Meguthang, Phalut, Prek Chhu, Thanggu, Thangkarphumoo, Thangshing.
Darjeeling: Sandakphu, Singalelah.

Ecology: Among rocks and in turf, stream and pathsides in fir or broad-leaf forests and Rhododendron scrub, 3,000–4,400m. Flowers July–September(–October).

Specimen List [64]

Acronema nervosum H.Wolff

Small plants with a slender stem from a small rhizome; stems 12–30cm, erect, unbranched, the underground part very thin and easily detached from the rhizome; rhizome globbose to oblong, 5–25 x 3–7mm. Leaves few, 1–2 basal and 1–2 cauline, ternate or pinnate, to 16 x 3cm (including the petiole); leaflets of basal leaves 0.5–2.5 x 0.4–1.7cm, ovate-elliptic, ternately lobed, sometimes deeply so, margin often serrately toothed in upper half; margins, midribs and secondary veins scaberulous above otherwise glabrous; upper leaves with narrower and more deeply cut segments; sheathing base of upper leaves very narrow, 1–2mm broad, almost absent in lower leaves. Primary umbel solitary and terminal, usually with just 1 smaller lateral secondary umbel close below; umbels 9–15mm across, 3–5-rayed; rays 3–6mm, elongating in fruit, slender and glabrous; bracts absent; umbellules 2–3mm across, 3–7-flowered; pedicels 2–3mm long, glabrous; bracteoles 2–3, linear, 1–2mm. Petals white to purple, 1.5–2 x 0.7–1mm, elliptic-ovate with a long acuminate apex, abruptly clawed at base, apex sometimes minutely pappilose. Stylopodium cream to dark purple, flattened; styles erect. Fruit ovoid-globbose, c 2 x 1.8mm.

Bhutan: C—Bumthang district (Dhur Chu); N—Upper Kulong Chu district (Me La).
Sikkim: Tsomgo.
Darjeeling?: Jaktok

Ecology: Open turf and amongst moss on rocks in fir forests, 3000–3700m. July–August

Specimen List [77]

Note: Endemic to the East Himalaya.

Acronema hookeri (C.B.Clarke) H.Wolff

Pimpinella hookeri C.B.Clarke

A rather robust erect, branching perennial (15–)25–110cm tall, from a small globose to oblong tuber; tuber to 6–12 x 4–8mm. Lower leaves pinnate then pinnate or ternate, or 2-ternate; leaflets ovate, to 3 x 2cm, serrate to deeply lobed, glabrous or margins and main veins above minutely papillose; ultimate segments elliptic-ovate, obtuse-mucronate at the apex; upper leaves with fewer, narrower segments; sheathing base of leaves narrow, 1–2mm broad. Umbels usually concentrated in upper half of stem forming a large lax group; umbels (2–)3–6-rayed; rays 8–18mm, slender; bracts and bracteoles 0–1, early falling, linear c 2mm; umbellules 3–5-flowered; pedicels 3–13(–17)mm long, slender and rather week. Petals creamy-white (occasionally purplish at base), lanceolate to 4 x 0.3mm, with a long densely puberulent cuneate-filiform tip over 2 x blade. Stylopodium flat-domed. Fruit ovoid to sub-globose, c 1.5 x 1.2mm.

Acronema hookeri (C.B.Clarke) H.Wolff var. hookeri

Bhutan: C—Thimphu district (Changri, Dotena, Talukah La) and Bumthang district (Bumthang); N—Upper Kuru Chu district (Julu).
Chumbi: Jork, Punkabeeseemoo.
Sikkim: Chungthang, Lachen, Lachung, Samdong, Tankra.

Ecology: On the ground in spruce, mixed broad-leaf and Rhododendron forest, 2150–3650m. Flowers July–August.

Specimen List [15148]

Note: Records from the area of the closely related A. paniculatum (Franchet) H.Wolff have proved to be referrable to this species.

Acronema hookeri (C.B.Clarke) H.Wolff var. graminifolium (W.W.Smith) H.Wolff

Pimpinella hookeri C.B.Clarke var. graminifolium W.W.Smith

Acronema graminifolium (W.W.Smith) S.L.Liou & R.H.Shan.

Differs from the typical variety in having all the leaves pinnatisect into linear-lanceolate segments (1.5–)4–7 x 0.2–0.35cm.

Bhutan: C—Thimphu district (Barshong to Dolam Kencho, Talukah La).
Chumbi: Punkabeeseemoo, Rinchengang.
Sikkim: Samdong, Yakche [Lit - Mukerjee & Constance] and Zemu Valley [Mukherjee,P.K. and Constance,L., 1993. Umbelliferae (Apiaceae) of India. New Dehli].

Ecology: Habitats as above, 2700–3600m. Flowers July–August.

Specimen List [15147]

Note: This narrow-leaved variety has been reported by several botanists to grow inter-mixed with the typical form.

Acronema sichuanense S.L.Liou & R.H.Shan

A small high altitude herb 1.5–5cm high, from a small ovoid tuber to 5mm thick. Leaves bi-ternate or ternate; leaflets ovate-elliptic, to 10 x 5mm, ternately incised or divided, glabrous; segments elliptic to narrowly so, linear in upper leaves, apex acute; sheathing petiole base rather broad to 3mm wide. Umbels mainly solitary and terminal, 3–6-rayed; rays 1–2cm, glabrous; bracts absent; umbelules 4–10-flowered; bracteoles 2–4, linear, 0.5–2mm; pedicels 1–4mm unequal, minutely scaberulous. Petals dark purple, linear subulate, 1–2 x 0.2mm. Stylopodium dark purple, flattened; styles spreading to recurved. Fruits globbose, c 1.5 x 1.5mm.

Bhutan: N—Upper Mo Chu district (Laya).
Sikkim: Zemu/Temu La.

Ecology: Alpine turf, 3900–4900m. Flowers August–September.

Specimen List [98]

Note: The above description refers to Bhutanese specimens which are smaller than the Chinese. Chinese material is more typically taller, 15–30cm high, with respectively larger leaves.

Acronema tenerum (DC.) Edgeworth

Helosciadium tenerum DC.

Pimpinella tenera (DC.) C.B.Clarke

Pimpinella tenera var. dissecta C.B.Clarke.

Stems (5–)8–25(–35)cm, slender and erect, from a small globose tuber 4–6mm across. Leaves to 7 x 2cm (including petiole), pinnate with 3–7 ovate leaflets (upper stem leaves often ternate); leaflets ovate, entire to deeply ternately lobed, 5–13 x 4–9mm, acute, base truncate or narrowed, margins serrate, minutely papillose on margins and veins above; ultimate lobes ovate-elliptic; sheathing base of petiole rather narrow, c 1.5mm broad. Umbels 2–4(–6)-rayed, laxly branched to 3cm across, lateral umbels well developed in leaf axils allong the whole stem; rays 6–13mm; bracts 0–1, lanceolate-linear, c 2mm, early falling; umbellules c 8mm across, laxly 3–4-flowered; pedicels 2–5mm, glabrous; bracteoles 3–5, narrowly ovate, 1–1.5mm. Petals purplish, narrowly lanceolate, 1–2mm, with a long acuminate to filiform apex minutely papillose at the tip.. Stylopodium cream-green, flat-domed; styles spreading. Fruit narrowly ovoid, c 1.5 x 1mm.

Bhutan: C—Thimphu district (Darkey Pang Tso, Taluka La) and Bumthang district (Rudo La).
Sikkim: Dzongri, Lachen, Lachung, Samdong.
Darjeeling: Singalelah.

Ecology: Often epiphytic in moss and leaf mould in fir forest, 3050-3800m. Flowers July–August.

Specimen List [88]

Note: Sometimes misidentified as A. muscicolum (Hand.-Mazz.) Hand.-Mazz.

Acronema pseudotenerum P.K.Mukherjee

Very slender-stemmed herb; stems unbranched, erect to 15cm high from a matted network of slender rhizomes; rhizomes to 30 x 2mm. Leaves basal and 1–3 cauline, pinnate with 5 leaflets or ternate; leaflets deeply ternately lobed to ternate; segments obovate to linear-lanceolate (uppermost leaves the linear-subulate), 2–5 x 0.5–4mm, glabrous, wider leaflets toothed or lobed in the upper half; sheathing bases rather conspicuous, 2.5–4mm broad to 10mm long in the upper leaves. Primary umbel solitary and terminal, usually with just 1 smaller lateral secondary umbel close below; umbels to 3cm across, 4–6-rayed; rays 7–15mm, elongating in fruit, slender and glabrous; bracts absent; umbellules c 1cm across, 6–9-flowered; pedicels 2–3.5mm long, glabrous or minutely papillate; bracteoles 0–3, linear, to 3mm. Petals white or suffused purple, narrowly elliptic to lanceolate, 1.3–2.7 x 0.5mm, with an acuminate apex, clawed at base. Stylopodium purplish, flattened; styles erect to spreading. Fruit ovoid-globbose, c 1 x 1mm.

Sikkim: Momay Samdong [Mukherjee,P.K. and Constance,L., 1993. Umbelliferae (Apiaceae) of India. New Dehli].

Ecology: Moss-covered boulders and logs in fir and rhododendron forest, 4200–5000m. Flowers June–August

Specimen List [97]

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