Siberian Whitlowgrass

Draba sibirica is very rare in China and is known to the present authors from a few collections, including Jiang Qingtang s.n., 24 Jun 1957 (PE), collected from Fuhai, Xinjiang. The species was first recorded from "Dscachor," Gansu by Maximowicz (Fl. Tangut. 65. 1889, as D. repens), but apparently no recent collections have been made from that province, nor was the species recorded from there in FRPS. The present record from Gansu is based on Przewalski s.n., 24 Jun 1880 (LE).

The descriptions and illustrations in FRPS (p. 166) and Fl. Xinjiang. (2(2): 112-113. 1995) of Draba sachalinensis Trautvetter are based on misidentified plants of D. sibirica, which is the only Chinese species with typically malpighiaceous leaf trichomes. True D. sachalinensis is highly restricted to E Russia (Sakhalin) and N Japan (Hokkaido, N Honshu); it does not occur in China.

Herbs perennial, 5-25 cm tall, scapose. Caudex with many, slender, creeping branches, sparsely covered with petiolar remains of previous years. Sterile stems subdecumbent, sparsely to densely hispid with malpighiaceous trichomes; flowering scapes sparsely pilose proximally with simple trichomes, often glabrous along distal half. Basal leaves subrosulate or not rosulate; petiole to 1 cm, persistent; leaf blade oblong-lanceolate or oblanceolate, 0.4-2.2 cm × 1-5(-10) mm, sparsely or densely hispid or strigose with appressed, malpighiaceous trichomes, these sometimes with 1 or 2, shorter lateral branches and appearing 3-fid or cross-shaped, sometimes adaxially or both surfaces glabrous except for margin, base attenuate, margin entire, always with malpighiaceous trichomes, apex acute. Cauline leaves of flowering stems absent, those of sterile shoots similar to basal ones. Racemes 7-20-flowered, ebracteate, glabrous, elongated considerably in fruit. Fruiting pedicels 0.5-1.8(-2.3) cm, divaricate, straight or curved, often filiform, glabrous. Sepals oblong or ovate, 2-2.7 × 0.9-1.2 mm, erect, glabrous or abaxially sparsely pilose with simple trichomes, base of lateral pair subsaccate, margin not membranous. Petals yellow, narrowly obovate, 4-6 × 2-3 mm, apex emarginate. Filaments 2-2.5 mm; anthers ovate-subcordate, 0.4-0.5 mm. Ovules 24-30 per ovary. Fruit oblong to elliptic, rarely sublinear, 4-8 × 1.5-2.2 mm, latiseptate, not twisted; valves glabrous, obscurely veined, base and apex subobtuse; style 0.5-1 mm. Seeds brown, ovate, 0.9-1.2 × 0.5-0.6 mm. Fl. May-Jul, fr. Jun-Aug. 2n = 16.

Gansu, Xinjiang [Kazakhstan, Kyrgyzstan, Mongolia, Russia].

Mountain slopes, sunny or shady wet places; 2000-2900 m.

Lepidium sibiricum Pallas, Reise Russ. Reich. 3: 34. 1776, not Schweigger (1812); Draba gmelinii Adams; D. repens Marschall von Bieberstein.