Description from Flora of China
Draba tibetica J. D. Hooker & Thomson var. winterbottomii J. D. Hooker & Thomson, J. Proc. Linn. Soc., Bot. 5: 152. 1861; D. dasyastra Gilg & O. E. Schulz; Ptilotrichum wageri Jafri.
Herbs perennial, (1-)2-7(-12) cm tall, densely or laxly cespitose, scapose. Caudex slender, often many branched, ultimate branches terminated in rosettes, covered with stramineous petiolar remains of previous years. Stems erect, simple, tomentose with subsessile stellate trichomes. Basal leaves rosulate; petiole absent, rarely to 6 mm, rarely ciliate; leaf blade obovate, oblong, spatulate, or lanceolate, 2-10 × 0.5-2 mm, densely tomentose with sessile or subsessile, very fine, 4-rayed stellate trichomes the rays of which with 1 or 2 lateral branches on each side, base attenuate to cuneate, margin entire, not ciliate, apex obtuse. Cauline leaves absent. Racemes 5-12-flowered, ebracteate, lax and elongated in fruit; rachis often flexuous, slender. Fruiting pedicels (3-)5-12(-15) mm, divaricate or rarely ascending, straight, tomentose all around with subsessile, stellate trichomes. Sepals oblong, 2-3 × 1-1.5 mm, erect, abaxially sparsely tomentose, base of lateral pair not saccate, margin narrowly membranous. Petals white, spatulate, 4-5 × 1.5-2.5 mm, apex subemarginate or rounded. Filaments 2-3 mm; anthers ovate, 0.4-0.5 mm. Ovules (10-)12-20 per ovary. Fruit narrowly elliptic, lanceolate, or oblong, (3-)5-9 × 1.5-2.3(-2.8) mm, not inflated, latiseptate, often twisted; valves glabrous or rarely puberulent, obscurely veined, base obtuse, apex acute; style (0.5-)0.7-1.3(-1.5) mm. Seeds brown, ovate, 0.9-1 × 0.7-0.8 mm. Fl. Jun-Aug, fr. Jul-Sep.
Ptilotrichum wageri was recognized as a distinct species in FRPS (p. 127), Fl. Xinjiang. (2(2): 105-107. 1995), and Fl. Xizang. (2: 344. 1985). However, an examination of its holotype, Wager 13 (K), clearly reveals that it is a synonym of Draba winterbottomii. No perennial species of Alyssum (including Ptilotrichum) has leafless scapes and more than four ovules per ovary. In his protologue of P. wageri (Notes Roy. Bot. Gard. Edinburgh 22: 208. 1957), Jafri erroneously stated that the ovary is 4-ovuled, though his hand-written comment on the holotype sheet correctly indicated that the ovary is 10-ovuled. The illustrations in Fl. Xinjiang. of two species of Ptilotrichum represent two forms of Alyssum canescens.
The record in FRPS (p. 141) of Draba incompta Steven from Xizang is based on misidentified plants of D. winterbottomii. True D. incompta is endemic to the Caucasus.
Grassy slopes, gravelly areas, glacial terraces; 4000-5900 m. Qinghai, Xizang [Kashmir, Pakistan].