CRUCIFER^E. (MUSTARD FAMILY.) 17 



eels glabrous. D. muricella, Wahl. ? of Bot. King's Exp. 21; D. nivalis of 

 Hayd. Rep. 1870. Uinta Mountains and far northward. 



2. D. crassifolia, Grah. Scape naked or with a single leaf, 1 to 3 

 inches high: leaves lanceolate-linear, entire or somewhat serrate, ciliate with 

 simple hairs : flowers small, yellow or white : petals a little exceeding the sepals, 

 retuse : pods ovate-elliptical, glabrous. Alpine, from Colorado northward, 

 and in California. 



3. D. alpina, L. Bather rigid : scape naked, mostly somewhat hirsute : 

 leaves spat ulate-lanceol ate, more or less pilose with branching hairs : petals yellow, 

 more than twice the length of the sepals : pods somewhat corymbed, oblong- 

 elliptical. Alpine, Colorado, Uintas, and northward to Arctic America. 



Var. glacialiS, Dickie. Dwarf: leaves more rigid, linear or narrowly 

 oblanceolate, more or less strongly carinate, stellate pubescent, not ciliate : pods 

 short-ovate, pubescent. D. glacialis of Hayd. Hep. 1871, 1872. Peaks about 

 Yellowstone Lake and far northward. 



# * Stems leafy. 

 t- Flowers white. 



4. D. incana, L. Hoary pubescent, seldom branching at the base : leaves 

 oblong-lanceolate, linear, or the lower spatulate: pods oblong-lanceolate , often 

 pubescent, on short erect pedicels. 



Var. eonf lisa, Poir. Leaves sparingly toothed : pods pubescent. Moun- 

 tains of Colorado and in British America. 



5. D. CUneifolia, Nutt. Hirsute-pubescent throughout with branching 

 hairs, usually branching at base, leafy below or only at base : leaves obovate or 

 spatulate with a narrow or cuneate base, sparingly toothed toward the apex : 

 pods linear-oblong, somewhat pubescent with short ascending hairs, on spread- 

 ing pedicels. Southern Colorado, eastward, and probably westward. 



1- -- Flowers yellow (white in one variety of No. 7). 

 -* Pods glabrous (except in one variety of No. 7). 



6. D. Stenoloba, Ledeb. Somewhat vilfous with spreading hairs, glabrous 

 above : stems erect, with divergent or decumbent branches near the base : 

 leaves oblanceolate, rather thin, rarely and sparingly toothed ; the cauline few 

 and sessile : petals bright or pale yellow : pods linear, in an elongated raceme 

 on spreading scattered pedicels ; style none. D. nemorosa, var. lutea, of Bot. 

 King's Exp. 22. Colorado mountains, the Uintas and Wahsatch, and west- 

 ward to California. 



7. D. nemorosa, L. Leaves oblong or someichat lanceolate, more or less 

 toothed : racemes elongated : petals emarginate, small : pods elliptical-oblong, 

 half the length of the horizontal or widely spreading pedicels. 



Var. leiocarpa, Lindb. Often with stem nearly or quite leafless, and 

 petals sometimes pinkish-white : sepals sparsely hirsute : pedicels scarcely ex- 

 ceeding or even shorter than the glabrous pods. D. nemorosa, var. lutea, of 

 Fl. Colorado and Hayd. Eep. 1871. Colorado and throughout Yellowstone 

 Park. 



Var. hebecarpa, Lindb. Pubescent : stem branched : pods pubescent, 

 one third the length of the pedicels. D. nemorosa of Bot. King's Exp. 22 and 

 Hayd. Rep. 1871. In the mountains from Colorado to Arctic America. 



2 



