42. Euphorbia donii Oudejans, Phytologia. 67(1): 45. 1989.
长叶大戟 chang ye da ji
Euphorbia longifolia D. Don, Prodr. Fl. Nepal. 162. 1825, not Lamarck (1788); Tithymalus longifolius Hurusawa & Yu. Tanaka.
Herbs, perennial, 20-60 cm tall. Rootstock woody, with many old stem bases, 20-30 cm × to 10 mm thick; roots fleshy, to 5 mm thick when dried. Stem single or several clustered, 2-5 mm thick, branched apically, glabrous. Leaves alternate, larger toward apex; stipules absent; lowermost leaves scalelike; petiole ± absent; leaf blade long elliptic to oblanceolate, 4-7 × 0.7-1.1 cm, slightly paler abaxially, glabrous, base cuneate or slightly rounded, margin entire, apex obtuse to subacute, mucronulate; midrib prominent abaxially, sunken adaxially, lateral veins 12 or more pairs, branching before margin. Inflorescence a terminal pseudumbel, sometimes with additional cymes from upper axils; primary involucral leaves usually 5, ovate-elliptic, 2.5-6 cm × 6-10 mm, base cuneate to ± rounded, apex obtuse to acute, primary rays 5, 3-4 cm; secondary involucral leaves usually 3, ovate-rounded, 1-2 × 0.5-0.8 cm; cyathophylls 2, ovate- rounded, 6-9 × 6-8 mm, base cuneate, apex rounded. Cyathium stipe 1-3 mm; involucre campanulate, ca. 3 × 2.5 mm, exterior glabrous, interior white pilose, lobes square, entire; glands 4, pale brown, rounded to transversely elliptic, entire. Bracteoles linear, densely pilose. Male flowers many, exserted from involucre. Female flower: ovary pedicel up to 4 mm and exserted from cup; ovary smooth, glabrous; styles connate to near middle; style arms shallowly 2-lobed, inconspicuous. Capsule ovoid-globose, 4-5 × 4-5 mm, smooth, glabrous. Seeds ovoid-globose, ca. 3 × 2 mm, dark brown, adaxially striate; caruncle peltate, yellow, sessile. Fl. and fr. Jun-Aug.
2000-2500 m. S Xizang (Nyalam) [Bhutan, N India, Nepal].