37. Draba linearifolia L. L. Lou & T. Y. Cheo, Fl. Xizang. 2: 346. 1985.
线叶葶苈 xian ye ting li
Herbs perennial, to 10 cm tall, densely cespitose, scapose. Caudex many branched, ultimate branches terminated in columnar rosettes and covered with spiny leaf midveins of previous years. Stems erect, slender, simple, pubescent with subsessile, forked and stellate trichomes. Basal leaves densely rosulate, persistent, sessile; leaf blade linear, 5-10 × 0.5-0.8 mm, abaxially subhirsute with subsessile, forked and 3-5-rayed stellate trichomes, adaxially densely hispid with simple trichomes, ciliate with setose simple trichomes to 1.5 mm, base attenuate, margin entire, apex acute; midvein very prominent abaxially to apex, usually as broad as or broader than blade on each side, 0.2-0.3 mm wide near base. Cauline leaves 1-3, sessile, oblong-linear, with indumentum similar to that basal leaves, margin entire, apex acute. Racemes 8-12-flowered, ebracteate, elongated in fruit. Fruiting pedicels 4-5 mm, divaricate-ascending, straight, pubescent all around with forked and stellate trichomes. Sepals oblong, ca. 1.5 × 0.9 mm, erect, abaxially pubescent, base of lateral pair not saccate, margin narrowly membranous. Petals yellow, drying white, narrowly obovate, 3-4.5 × 1-1.5 mm, apex obtuse. Filaments ca. 1.5 mm; anthers ovate, ca. 0.2 mm. Fruit linear-lanceolate, 7-10 × 1-1.3 mm, not twisted; valves glabrous, obscurely veined, base and apex subacute; style 0.5-1 mm. Mature seeds not seen. Fl. and fr. Jun-Jul.
* Shady mountain slopes; 3600-4000 m. Xizang.
Draba linearifolia, which is known only from the type collection, Qinghai-Xizang Expedition 4074 (holotype, PE), is readily distinguished from all other Chinese species by having basal leaf midveins persistent into spines.