CRUCIFERAE (MUSTARD FAMILY) 221 



ing; silique ovate to lanceolate or linear. Seeds in 2 rows, not winged or 

 margined. Pubescence simple or branched. 



Annuals or winter annuals. 



Silique glabrous; flowers yellow, sometimes turning white in 



drying. 

 Style wanting. 



Stems scapose, glabrous . . . . . . . 1. D. crassifolia. 



Stems scapose, ciliate-hirsute below . . . . 2. D. nitida. 



Style evident . . . . . . . . 3. D. mongollonica. 



Silique pubescent; stigma sessile. 

 Flowers white. 



Leaves entire; siliques in a terminal cluster . . 4. D. caroliniana. 



Leaves toothed or entire; siliques in a somewhat elongated 

 raceme. 



Pedicels ascending or erect 5. D. cuneifolia. 



Pedicels reflexed . 6. D. reflexa. 



Flowers yellow. 



Pedicels longer than the silique 7. D. nemorosa. 



Pedicels shorten than the silique 8. D. lapilutea. 



Perennials. 



Low, caespitose, and scapose; leaves imbricated. 



Scape pubescent . . . . . . . . . 9. D. densifolia. 



Scape glabrate; silique ovate. 



Flowers white 10. D. oligosperma. 



Flowers yellow. 



Silique broadly ovate . . . . . . .11. D. andina. 



Silique ovate-oblong 12. D. saximontana. 



Taller; stems more or less leafy. 



Siliques glabrous or nearly so, not twisted. 

 Flowers yellow. 



Pubescence branched; flowers large .... 13. D. spectabilis. 



Pubescence simple; flowers small ..... 14. D. chrysantha. 



Flowers white, small . . . . . . . . 15. D. cana. 



Siliques pubescent, more or less twisted. 



Pubescence of herbage long and villous .... 16. D. streptocarpa. 



Pubescence of herbage short and stellate. 



Leaves large and thin . . . . . . . 17. D. surculifera. 



Leaves rather small and firm. 



Silique with flat valves, glabrate on the face . . 18. D. Helleriana. 

 Silique with convex valves, pubescent . . .19. D. luteola. 



1. Draba crassifolia Graham, Edinb. New Phil. Journ. 182. 1829. Gla- 

 brous throughout or with the leaves sparsely ciliate, annual or biennial: scape 

 naked or with a single leaf, 5-10 cm. high: leaves lanceolate-linear, entire or 

 somewhat serrulate, ciliate with simple hairs: flowers small, white or yel- 

 lowish; petals a little exceeding the sepals, retuse: siliques oblong-lanceolate, 

 acute, 5-9 mm. long, on spreading pedicels of about the same length. (D. 

 Parryi Rydb. Bull. Torr. Bot. Club 29: 241. 1902.) High mountains; Colo- 

 rado to British America. 



2. Draba nitida Greene, PL Baker. 3: 7. 1901. Erect annual 1-3 dm. high, 

 glabrous and somewhat shining: stems 1 or more from the base, ciliate-pubescent 

 below only: leaves mostly in a rosulate tuft at the base, sparsely substel- 

 late, the margins loosely bristly-ciliate : raceme long in fruit: petals yellow, 

 longer than the green somewhat pilose sepals: silique oblong-linear, acutish, 

 10-15 mm. long, on ascending pedicels of about the same length. D. stenoloba. 

 At middle or higher elevations; Colorado to Montana. 



3. Draba mongollonica Greene, Bot. Gaz. 6: 157. 1882. Somewhat scapose 

 annual, 2-4 dm. high, villous or loosely stellate-pubescent below: stem simple 

 or branching from the base: leaves oblanceolate, stellate-pubescent, 3-6 cm. 

 long: flowers large, in broad racemes which are elongated in fruit: sepals 

 glabrous: siliques linear or oblong, glabrous, 8-15 mm. long, with a slender 

 style 2-3 mm. long; pedicels slender, variable, longer or shorter than the 

 silique. Infrequent; New Mexico and probably southern Colorado. 



4. Draba caroliniana micrantha Gray, Man. Ed. 5. 72. 1867. Low, usually 

 less than 1 dm. high: leaves obovate or oblanceolate, entire, rosulate or 

 crowded near the base, loosely stellate-pubescent, 10-12 mm. long: scapose 

 stems few or several from the crown, glabrous or pubescent: flowers small, 

 white, the pedicels closely approximate even in fruit: siliques minutely hispid, 

 10-15 mm. long, much exceeding the divergent pedicels. This variety does 



