MUSTARD FAMILY 105 



Perennials; style usually evident. 



Plants scapose or nearly so. « 



Pod 16-20 mm. long and 7-8 mm. wide. 15. D. eurycarpa. 



Pod less than 12 mm. long and 5 mm. wide. 

 Petals yellow. 



Pods about twice as long as broad, 5-12 mm. long. 

 Pods glabrous or nearly so. 



Leaves not stellate, glabrous, except the ciliate margin. (Depauperate 

 variety of) 41. D. strepiocarpa. 



Leaves more or less stellate over the whole surface. 



Leaves broadly spatulate, long-ciUate, especially on the margin; 



midrib weak. 16." D. alpina. 



Leaves linear-oblanceolate, scarcely ciliate; midrib strong. 



17. D. glacialis. 

 Pods pubescent. 



Leaves obovate, densely and finely white-stellate; midrib indistinct. 



18. D. argyrea. 

 Leaves spatulate or linear-oblong, sparingly stellate, with a strong 



midrib. 

 Plant cespitose, but not densely pulvinate; leaves oblanceolate 

 or spatulate, rather finely stellate, spreading, not densely 

 imbricate. 19. D. incerta. 



Plant densely pulvinate; leaves linear-oblong, villous-hispid as 

 well as stellate, densely imbricate. 20. D. densifolia. 



Pods only slightly longer than broad. 



Leaves stellate or with branched hairs. 

 Pod ovate or elliptic, compressed. 



Pods densely stellate, about 5 mm. long, fully 4 mm. wide; 

 midrib of the leaves indistinct. 

 Leaves densely and closely stellate, thick. 



21. D. rentrosa. 

 Leaves sparingly long-hairy or glabrate above. 



22. D. sobolifera. 

 Pods sparingly puberulent or glabrous, not more than 3 mm. 



wide, .3-5 mm. long. 

 Leaves oblong to hnear; midvein strong. 



Plants not densely pulvinate; leaves Linear or linear-ob- 

 lanceolate, 5-10 mm. long. 23. D. oligosperma. 

 Plant densely pulvinate; leaves oblong or Unear-oblong, 

 less than 5 mm. long, densely imbricate. 



24. D. andina. 

 Leaves obovate, thick; midvein indistinct. 



25. D. uncinalis. 

 Pod globose. 26. D. sphaerocarpa. 



Leaves glabrous except the imbranched ciliations on the margins. 

 Leaves densely imbricate, short. 



Pod pubescent ; midvein of the leaves obsolete. 



27. D. sphacrula. 

 Pod glabrous; midvein of the leaves prominent. 



28. D. pectinata. 

 Leaves not densely imbricate; pod pubescent, 3-6 mm. long. 



„ 29. D. Nelsonii. 



Petals wlute. 



Leaves finely stellate. 



Leaves Unear or linear-oblanceolate. 



Midrib of the leaves strong; pods 4-5 mm. long. 



23. D. oligosperma. 

 Midribs of the leaves not strong; pods 6-8 mm. long. 



30. D. lapponica. 

 Leaves broadly spatulate or obovate. 

 Pod oblong to Unear, 6-12 mm. long. 



Pods 6-8 mm. long, not twisted. 31. D. nivalis. 



Pods 10-15 mm. long, more or less twisted. 32. D. lonchocarpa. 

 Pods broadly obovate, 3—4 mm. long. 25. D. uncinalis. 



Leaves liirsute-ciliate on the margins, oblanceolate. 



Style obsolete. 33. D. fladnizensis. 



^, Style about 1 mm. long. 34. D. oreibata. 



Plant leafy -stemmed. 

 Petals white. 



Petals about 3 mm. long; pods 5-8 mm. long. 



Plant 1-2 dm. liigh, densely grayish-stellate; pods longer than the pedicels. 



35. D. cana. 

 Plants about 3 dm. high, greener; pods shorter than the pedicels. 

 „ , , 36. D. McCallae. 



Petals about 2 mm. long; pods more than 1 cm. long. 37. D. columbiana. 

 Petals yellow. 



Plants glabrous, except the margins of the leaves, which are occasionally cili- 

 ate. 

 / Leaves linear or narrowly linear-oblanceolate, thin. 



Leaves much shorter than the flowering stem; pods lance-linear. 



^ , 38. D. chrysantha. 



Leaves almost equalling the flowering stem; pods ovate. 



39. ID. graminea. 



