28 CRUCIFER^. Draha. 



equal. Filaments mostly flattened, without teeth. Anthers rounded or oval. — 

 Low annual or perennial herbs ; Avith entire or toothed leaves and white or yeUow 

 flowers, 



A large genus, of nearly a hundred or more species, mostly inhabitants of cool climates, and 

 many alpine or arctic. The limits of many of the species are with difficulty defined, and author- 

 ities difier much in their views respecting them. 



* Annual or biennial, ivith leafy stems : 2>et<xls usually emarginate. 



1. D. cuneifolia, Nutt. Hirsute-pubescent throughout with branching hairs : 

 stems usually branching at base, 3 to 6 inches high, leafy below or only at base : 

 leaves obovate or spatulate with a narrow or cuneate base, | to 1 inch long, spar- 

 ingly toothed toward the apex : petals white, 1 J to 2 lines long, twice as long as 

 the sepals : pod linear-oblong, 3 to 6 lines long, acutish, somewhat pubescent with 

 short ascending hairs, on spreading pedicels 1 to 3 lines long : style none. — Torr. 

 & Gray, Fl. i. 108. 



Frequent east of the Colorado to Texas and the Mississippi Valley. Eeduced specimens were 

 collected at Los Angeles by Gamhel, and a more doubtful form by Brewer in the Temescal Moun- 

 tains, near the tin mines. The latter specimens are scarcely an inch high, the leaves obovate- 

 spatulate, only two lines long and entire, the flowers smaller (a line long), and the young capsule 

 broader in proportion and glabrous. 



2. D. Stenoloba, Ledeb. Somewhat villous with spreading hairs, glabrous 

 above : stems erect, slender, 4 to 12 inches high, with divergent or decumbent 

 branches from near the base : leaves oblanceolate, | to 1 inch long, rather thin, 

 acute, rarely and sparingly toothed, ciliate and slightly villous-pubescent ; the 

 cauline few and sessile: petals bright or pale yellow, 1 to H lines long, half longer 

 than the calyx, obtuse : pod linear, 3 to 5 lines long, acute at each end, glabrous, 

 in an elongated raceme, on spreading scattered pedicels 2 to 4 lines long : style 

 none. — Fl. Eoss. i. 154. D. nemorosa, var. lutea, Watson, Bot. King Exp. 22. 



Dry soils in the Sierra Nevada, at 7,000 to 10,000 feet altitude, from Yosemite Valley and 

 Mono Pass {Brevier, Gray) to Donner Pass {Greene), and eastward in the Wahsateh and Yuintahs 

 {Watson) and Colorado. It appears to be identical with the original Unalaschkan form. It is 

 readily distinguished from D. nemorosa, with which it has been confounded and which is frequent 

 in the mountains from Washington TeiTitory to Colorado, by its thinner, narrower and more 

 entire leaves and its shorter pedicels. 



* -V: Biennial or j^erennial. 



-i- Stems leafy. 



3. D. aurea, Yahl. Biennial, more or less canescently stellate-pubescent and 

 usually somewhat villous with branching hairs : stems 3 to 18 inches high, solitary 

 or several from the same root, simple or branched, leafy : leaves oblanceolate and 

 petioled, ^ to 2 inches long, the upper sessile and oblong to oblong-ovate, acute, 

 entire or sometimes sparingly toothed : petals yellow turning to white, twice longer 

 than the calyx, rounded at the apex or emarginate : pod linear-lanceolate, 4 to 6 

 lines long, attenuate upward into the short style, puberulent, often somewhat 

 twisted. —Fl. Dan. t. 1460. Hook. Bot. Mag. t. 2934. 



In the Kocky Mountains from Colorado to British America. Specimens collected by Brcicer 

 on Mt. Dana at 12,000 feet altitude, and by Lcminon fartlier north in the Sierra Nevada, must 

 apparently be referred here though they have more of a perennial habit than is usual in the spe- 

 cies. Their basal leaves are densely crowded, and the whole jdant, including the pods, densely 

 stellate-pubescent. 



+- -f- Stems naked and scape-like above the base, few-fiowered. 



4. D. crassifolia, Graham. Biennial or perennial (sometimes apparently annual), 

 glabrous : stems slender, 1 to 5 inches high, solitary or few from a very short and 

 nearly simple rootstock : leaves rosulate, thin, flat, narrowly oblanceolate or linear, 

 ;^ to 1 inch long, rarely with 1 or 2 lateral teeth, more or less ciliate with long hairs : 



