Flora of Bhutan Umbelliferae: Bupleurum

Bupleurum L. Mark F. Watson

Annual or perennial, glabrous, often rather glaucous herbs. Leaves entire, usually at length parallel veined. Umbels loosely compound, bracts and bracteoles leaf-like (or absent). Flowers yellow, sometimes tinged green or purple, shortly stalked. Calyx teeth absent. Petals obovate, emarginate. Stylopodium broadly conical. Fruit oblong or ovoid, slightly compressed laterally, mericarps subterete, somewhat prominently 5-ribbed.

Note: A distinctive genus where the specific limits are as yet not properly defined. Further work is needed covering the Sino-Himalayan representatives as a whole.

Key to species

1	Annuals or short-lived perennials; inflorescences diffusely branched, rays very slender; flowers yellow-green; fruit ovoid, ribbed	*B. hamiltonii*
+	Perennials; inflorescences erect, rays slender to more robust; flowers yellow-green or purple; fruit oblong to ovoid, ribbed or winged	2

2	Plants usually <40cm tall, stems numerous (>5) and often decumbent from a woody tap-root	3
+	Mature plants >40cm tall, stems few, erect	4

3	Bracteoles 4(–5), broadly elliptic-ovate; umbellules 1–4 per umbel	*B. dalhousieanum*
+	Bracteoles 5–6, linear to linear-ovate; umbellules >5 per umbel	*B. gracillimum*

4	Mid stem leaves ovate-elliptic to oblanceolate, >1.5cm wide, cuneate or rounded at base; umbellules numerous, usually >8 per umbel	*B. candollei*
+	Mid stem leaves narrower, usually <1.5cm wide, long attenuate at base; umbellules <8 per umbel	5

5	Mid stem leaves expanded at base and clasping the stem; bracteoles numerous, >7 per umbellule, ovate, conspicuously longer than the purple flowers; fruits prominently winged	*B. himalayense*
+	Mid stem leaves attenuate at base; bracteoles usually <7 per umbellule, narrower than above and about as long as the yellow-green flowers; fruits with prominent ribs but not as above	6

6	Leaves with broad whitish cartilaginous margin; bracteoles linear-lanceolate, about half as long as the flowers and shorter than the fruiting pedicels	*B. marginatum*
+	Margin of leaves not as above; bracteoles narrowly ovate, about as long as the flowers and longer than the fruiting pedicels	*B. falcatum*

Bupleurum hamiltonii N.P.Balakrishnan

Bupleurum tenue D.Don.

Erect stemmed annual to 75cm, often single-stemmed, woody at base and rather diffusely branched above, base of stem, leaf and bract margins often tinged red. Leaves linear-elliptic 2–7 x 0.2–1.1cm, rounded at apex with a tiny mucro, base cuneate to attenuate, sometimes finely brownish spotted. Umbellules very small, c 5mm across, 5–11-flowered, 2–5(–7) per umbel; bracts 2–3, small, unequal, narrowly elliptic, c 4 x 2mm; rays very slender; bracteoles 4–7(–10) narrowly elliptic 2–4 x 1–1.5mm, acuminate, as long as or slightly longer than flowers. Petals yellow-green with a brown midrib on the reverse. Fruit ovoid c 2 x 1.5mm, ribs whitish, prominent but not winged; fruiting pedicels shorter than bracteoles.

Bhutan: C—Punakha district (Wache).

Ecology: Open grassy slopes and rocky hillsides. 1000–2000m. Flowers July–September.

Specimen List [2563]

Bupleurum dalhousieanum (C.B.Clarke) Koso-Poljansky

Bupleurum longicaule DC. var. dalhousieanum C.B.Clarke

Decumbent to erect perennial (5–)10–20(-)-35cm tall, with several to many, sparingly-branched stems arising from a woody tap-root. Leaves membranous with obscure reticulate veining appearing parallel: basal and lower leaves linear to linear-oblanceolate 2–8 x 0.15–0.4cm, obtuse-acute, long attenuate at base; middle leaves linear-lanceolate to lanceolate, (1–)2–6.5 x (0.2–)0.4–1cm, acute, base rounded or abruptly cuneate, semi-amplexicaul; uppermost leaves broadly lanecolate, 1–2.5(–4) x 0.4–0.6(–1)cm, acute, rounded to cordate at base and distinctly amplexicaul. Umbellules 4–6(–10)-flowered, 5–10mm across, 1–4 per umbel, rays somewhat unequal; bracts 2–3, unequal, the larger like the upper cauline leaves 9–24 x 4–8mm; bracteoles 4(–5), broadly elliptic-ovate, 2.5–6 x 2–4mm, obtuse-acuminate, equal to or slightly longer than flowers. Petals dull blue to dark purple. Stylopodium dark purple-red. Fruit ovoid, 3–4 x 1.5–2.3mm; pedicels shorter than the fruit.

Bhutan: C—Punakha district (Tang Chu); N—Upper Bumthang Chu district (Dole La, Kantanang-Tsampa) and Upper Kulong Chu district (Shingbe).
Chumbi?: Lingter.
Sikkim: Chiya Bhanjang, Dzongri, Meguthang, Nathang, Tsomgo, Yak La.

Ecology: Open hillsides, meadows, pathsides, etc. 3050–4600m. Flowers (May–)June–July.

Illustration [Fig 50 d-f]

Specimen List [2066]

Note: Sometimes considered as just an altitude form of B. longicaule, but here treated as a morphologically distinct species. Bupleurum sikkimensis P.K.Mukherjee is only reported from its type specimen (in fact probably collected in Chumbi). It is said to differ from B. dalhousieanum by its unwinged fruits, 3 vittae between the fruit ribs (4 on the comissural face) and obtuse leaves. It is not included here as no specimens have been seen.

Bupleurum gracillimum Klotzsch

Bupleurum falcatum L. var. nigrocarpum Jacquemont

Bupleurum virgatum Wall.

Slender tap-rooted perennial with many (usually more than 5) slender little-branched stems, prostrate to decumbent, or erect, up to 35(–60)cm long. Lower leaves linear-oblanceolate, 1.5–3 x 0.15–0.3cm, obtuse-acute to -acuminate, base attenuate, usually numerous and crowded; stem leaves linear to lanceolate 2–5(–6.5) x 0.15–0.3(–0.5)cm, acuminate, base cuneate to rounded, semi-amplexicaul; uppermost leaves sometimes wider. Flowers dark purple. Umbellules 5–10(–15)-flowered, 3.5–6mm across in flower, 2–5(–6) per umbel, primary rays slender. Bracts 1–3, lanceolate to lanceolate ovate, unequal, to 8 x 2.5mm; bracteoles 5–6, linear to linear-elliptic 4–5 x 1mm, acute–acuminate, about as long as flowers. Fruit ovoid c 3.5 x 2mm, vittae in 3 lines per furrow between the prominent ribs, pedicels shorter than the fruit.

Bhutan: C—Thimphu district (Barshong, Dakey Phungtso); N—Upper Mo Chu district (Laya, Lingshi La).

Ecology: Open areas, streamsides, tracks, etc. 2800–4000m. Flowers July–August.

Specimen List [2357]

Bupleurum candollei DC.

Bupleurum longicaule auct non DC.

Perennial with a few erect stems 75–130cm tall, usually sparingly branched, from a short, woody horizontal rhizome. Leaves very variable in shape and size, membranous with reticulate veining (sometimes obscure appearing parallel), and a narrow cartilaginous margin: basal and lower leaves linear-oblanceolate(-spathulate), (3–)6–12 x (0.2–)0.5–1.5cm, obtuse-acute, attenuate at base, often withered at flowering; middle leaves ovate-elliptic to lanceolate or oblanceolate, (3–)5–10 x(0.8–)1.5–2.8cm, obtuse-acute, mucronate, attenuate to rounded at base, semi-amplexicaul, sometimes cordate-amplexicaule; uppermost leaves often ovate, (1.5–)2–4 x (0.6–)0.8–1.4cm, acute, rounded at base and amplexicaul. Umbellules (14–)15–20-flowered, 7–12(–15)mm across, (6–)8–15(–22) per umbel, rays somewhat unequal; bracts 2–3(–4), unequal, leaf-like, to 25 x 11mm; bracteoles usually 5, elliptic–ovate, 4–8 x 2.5–4mm, acute or obtuse-acuminate, equal to or slightly longer than flowers. Petals yellow or tipped purple, sometimes appearing dark blue or purple-black. Stylopodium dark purple-red. Fruit oblong-ellipsoid 3.5–4.5 x 2mm.

Bhutan: C—Thimphu district, Bumthang district (Bumthang, Gyetsa) and Mongar district (Sengor); N—Upper Mo Chu district (Lingshi).
Chumbi: Bakcham, Chumbi, Yeum-chung.
Sikkim: Lachen, Lachung, Phalut, Tari, Tsomgo.
Darjeeling: Phullalong, Sandakphu.

Ecology: Common in open areas; grassy hillsides, streamsides, forest clearings, etc. 2300–4000m. Flowers June–August.

Specimen List [2064]

Note: A problematic species needing further work, here treated as one variable entity. Several infraspecific taxa have been described but none are truly distinct. The elliptic-lanceolate leaf form characteristic of Wallich's type gathering (Wall. Cat. No. 552) intergrades across the geographic range of the species (NW India to Bhutan, Tibet and Burma) into specimens with broad amplexicaul bases, and narrowly lancolate/oblanceolate leaves more reminiscent of elements of the Wallich (mixed) type collection of B. longicaule (Wall. Cat. No. 557). The parallel versus reticulate veining character, and number of veins are not reliable differentiators. The true identity of B. longicaule needs to be established. It may prove to be conspecific with B. candollei and if so should be included under the latter name.

Bupleurum himalayense Klotzsch

Bupleurum longicaule var. himalayense (Klotzsch) C.B.Clarke

Erect to decumbent perennial with a few, little-branched stems 18–60cm long, from a vertical to horizontal tap-root. Lower leaves narrowly oblanceolate, 3–8 x 0.15–0.35cm, apex acuminate to obtuse-acute, base long attenuate and semi-amplexicaule; stem leaves distinctively shaped, oblanceolate 5–12 x 0.3–1cm, apex long acuminate, base auriculate rounded to subcordate, amplexicaule. Flowers dark purple. Umbellules 18–40-flowered, 10–17mm across, 3–5 per umbel; bracts 1–3, ovate acuminate, unequal, to 20 x 7mm; bracteoles (6–)7–8, ovate 6–12 x 3–5mm, distinctly longer than the flowers, apex acute to shortly acuminate, base rounded. Fruit oblong, 3.5– x 1.5–mm, ribs prominently broadly winged; fruiting pedicels shorter than the bracteoles.

Sikkim: Lachen, Thanggu.

Ecology: Grassy slopes and forest clearings, 3300–4000m. Flowers July.

Specimen List [2369]

Bupleurum marginatum DC.

Bupleurum falcatum L. var. marginatum (DC.) C.B.Clarke

Erect perennial with a few stout stems 60–75cm high, arising from a woody horizontal rhizome; stems usually corymbosely branched towards the apex. Leaves linear-lanceolate or oblanceolate 6–15 x 0.3–0.8cm, acuminate, base attenuate amplexicaul, whitish cartilaginous margin conspicuously wide. Flowers yellow. Umbellules 6–12-flowered, 5–10mm across, 4–8 per umbel; bracts 2–5, small, unequal, linear c 4 x 1mm; bracteoles 4–5, lanceolate 1.5–2.5 x 1mm, acuminate, about half as long as flowers. Fruit oblong-ovoid 3–4 x 2–2.5mm, ribs prominent, whitish; pedicels distinctly longer than bracteoles in fruit.

Bhutan: C—Punakha district (Tang Chu) and Mongar district (Lhuntse).
Chumbi?: Yam Dok Cho.
Sikkim: Lachen.

Ecology: Forest clearings and grassy hillsides. 1300–1850m. Flowers May–June.

Specimen List [2071]

Bupleurum falcatum L.

Perennial herb with erect, often shortly decumbent stems to 80cm high. Leaves linear-oblanceolate, 4–11 x 0.2–0.4cm, apex acute, long attenuate at base, rather coarse textured with prominent parallel veins below. Umbellules small, 5–7mm across, 8–10-flowered, 5–7 per umbel; bracts 2–3, unequal, narrowly ovate-lanceolate, acuminate, to 5 x 1mm, prominently, strongly 3-veined below; rays slender; bracteoles similar to the bracts, as long as flowers. Petals yellow-green with brown midrib on the reverse. Fruit oblong, c 5 x 1mm, ribbed but not winged.

Bhutan: C—Thimphu district (Paya, Tsalimphe to Simo-Sampa) and Tashigang district (Tashi Yangtsi); S—Upper Mo Chu district (Chusom).

Ecology: Dry stony hillsides and rough pastue. 2100m. Flowers July–August.

Specimen List [2330]

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