Flora of Bhutan Umbelliferae: Physospermopsis

Physospermopsis H.Wolff Mark F. Watson

Dwarf or medium-sized, glabrous perennials, usually with fibrous leaf remains at base. Leaves pinnate, leaflets serrate, pinnatifid or pinnatisect; petiole slightly winged and sheathing at base. Umbels compound, rays unequal; bracts leaf-like; umbellules small; bracteoles serrate, often 3-lobed. Calyx teeth minute or absent. Petals, white, greenish or purple, obovate, somewhat unequal, inflexed at apex, attenuate at base. Stylopodium thickly conical or flattened. Fruit ovoid-globose, slightly laterally compressed, glabrous, immature mericarps a characteristic verde-gris (emerald green) colour turning dark purple on maturity; young fruit prominently 5-ribbed, not winged.

Note: A complex genus, apparently greatly affected by environmental conditions. Discontinuities in the observed variation in stature, leaf, bract and bracteole shape across the geographic range are difficult to determine. Field notes and literature records have suggested that this may be accounted for by phenotypic plasticity. Further experimental work on living plants is needed to elucidate the true picture, as herbarium material is so often inadequate.

Key to species

1	Plants mainly >15cm high; immature fruits obovate becomming ovoid, stylopodium conically domed	*P. obtusiuscula*
+	Plants mainly <15cm high; fruits somewhat rectangular, stylopodium flattened	*P. kingdon-wardii*

Physospermopsis obtusiuscula (DC.) C.Norman

Trachydium hirsutulum C.B Clarke

Trachydium obtusiusculum (DC.) C.B.Clarke

Trachydium obtusiusculum (DC.) C.B.Clarke var. strictum C.B.Clarke

Physospermopsis farillei P.K.Mukherjee & Constance

Physospermopsis hirsutulum (C.B Clarke) Farille

Plants (6–)15–40(–60)cm tall, sometimes tinged red. Leaves 6–20 x 2–4 cm (including petiole), mainly basal; pinnae in 2–4 pairs, ovate to elliptic in outline, 6–25 x 4–18(–24)mm, deeply ternately lobed to pinnatifid, ultimate segments lanceolate, apices acute, margins serrate and minutely denticulate; petioles 3.5–10cm. Flowering stem of greatly varying length, usually sparsely leafy, bearing a solitary terminal umbel and sometimes a few smaller laterals. Umbels 7–18cm across, 8–14-rayed; rays 2–13(–18)cm long, becomming more erect in fruit; bracts leaf-like, broadly oblanceolate in outline, 2–4 x 1–1.25cm, base winged (margin sometimes pale), blade pinnate to pinnatifid, midribs conspicuous, usually covered with minute flattened papillae; umbellules 1.2–3cm across, (8–)18–30-flowered; pedicels 3–7mm; bracteoles lanceolate to elliptic in outline, 6–20 x 1.5–6mm, simple or acutely 3-lobed (middle lobe sometimes coarsely 3-toothed), segments usually quite broad but occasionally narrow. Petals white, dark greenish or purple, obovate, c 2mm. Stylopodium conically-domed, more than half as tall as broad, base often forming a thickened ring with the top of the fruit. Fruits ovoid, often constricted in the upper half when young, 2.5–3 x 1.2mm.

Bhutan: C—Thimphu district (Bimelang Tso, Darkey Pang Tso, Gyida, Saga La, Simtokha, Tataka); N—Upper Mo Chu district (Tharizam Chu).
Chumbi: Yak La.
Sikkim: Cho La, Dzongri, Kangling, Lachung, Thanggu, Yume Samdong.

External Distribution: Nepal, SE Tibet.

Ecology: Exposed upland and alpine turf, woodland margins, open rocky areas. 3000–4300m.
Flowers July–August.

Specimen List [10929]

Note: Some plants collected in Nepal (including the lectotype) and Sikkim are very long-stemmed and have larger leaves and bracts. They appear to intergrade continuously with the plants to the east. Stature appears to be variable according to environmental conditions, exposure, light availability, grazing pressure, etc.

Physospermopsis kingdon-wardii (H.Wolff) C.Norman

Trachydium kingdon-wardii H.Wolff

Physospermopsis bhutanensis M.A.Farille & S.B.Malla.

Similar to P. obtusiuscula but acaulous or shortly stemmed up to 10(–30)cm. Leaves 3–7 x 1–2cm (including petiole); pinnae in 3–4 pairs, broadly ovate 4–7 x 3–7mm, deeply ternately lobed, lobing becoming shallower towards the leaf apex; segments ovate-oblong, wider and somewhat less dissected than P.obtusiuscula. Umbels 5–8 rayed; rays 2–5cm; umbellules 10–14mm across; pedicels up to 6mm; bracteoles similar to P. obtusiuscula, but less dissected, 4–7mm, entire to 3-lobed, coarsely toothed near apex, often longer than the flowers and fringing the umbellule. Petals white to purple. Stylopodium broad and flat, styles cream. Fruit rather rectangular in outline, base truncate, immature dried mericarps often with wavy ridges.

Bhutan: C—Thimphu district (Kangla to Ha, Paglekacheram); N—Upper Mo Chu district (Chomo Lhari, Lingshi), Upper Pho Chu district (Gyophu La), Upper Bumthang Chu district (Pangtang), Upper Kuru Chu district (Gong La) and Upper Kulong Chu district (Singbe).
Chumbi: Chaerlung, Chomo Lhari.
Sikkim: Bikbari, Chemathang, Chomnago, Dzongri, Lachen, Lam Pokhri, Thanggu.

Ecology: Alpine meadows. 3600–4880m. Flowers (June–)July–September.

Illustration [Fig 49 h-i]

Specimen List [10928]

Note: Apparently flowering slightly later than P. obtusiuscula and usually from somewhat higher elevations.

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