Bhutanese representatives are essentially glabrous, slender little-branched annuals with short fusiform tap-roots. Leaves biternate or pinnatisect; petioles slender with ovate sheathing bases. Umbels compound, mainly terminal; rays somewhat unequal; bracts absent; umbellules 2–3-flowered; pedicels very short and conspicuously unequal; bracteoles present, linear. Calyx teeth minute triangular. Petals white to purplish, ovate, acute spreading or incurved. Stylopodium domed. Fruit ovoid-ellipsoid, slightly compressed laterally, mericarps weakly ribbed, smooth.
Key to species
Pternopetalum radiatum (W.W.Smith) P.K.Mukherjee
Acronema radiatum (W.W.Smith) H.Wolff
Pternopetalum delicatulum (H.Wolff) Handel-Mazzetti
Bhutan: C—Bumthang district
(Lami Gompa) and Thimphu district (Dotena to Barshong, Hongsto); N—Upper
Kuru Chu district (Julu).
Ecology: Damp shaded banks in hemlock and fir forests, 3100–3400m. Flowers June–July.
Illustration [Fig. 51 l,m]
Specimen List 
Pternopetalum subalpinum Handel-Mazzetti
Delicate unbranched herb, 5–10(-20)cm tall. Leaves almost entirely basal, 3–8 x 0.6–1.5cm (including petiole), pinnate with (1-)2–4 pairs of leaflets; leaflets broadly ovate, 2.5–7 x 1.5–8mm, acutely 3-lobed, often deeply so, almost glabrous; petiole 3–5cm. Umbels entirely terminal, 5–10-rayed; rays 1.5–3.5cm, filiform, unequal; umbellules mostly 2–flowered; pedicels 0.2–2mm; bracteoles 2, 0.75–1.5mm. Petals white to purplish. Styles purple. Fruits c 1.5 x 0.75mm.
Bhutan: C—Tongsa district
(Yuto La); N—Upper Mo Chu district (Kohina) and Upper Kulong Chu
Ecology: Shaded mossy banks and rocks in fir forests, 3000–3550m. Flowers June-July.
Specimen List 
Note: Literature references to P. tanakae (Franchet & Savatier) Handel-Mazzetti occuring in Bhutan are based on a misidentifed specimen of P. subalpinum.