MUSTARD FAMILY 105 



Perennials; style iisually evident. 

 Plants scapose or nearly so. 



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



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

 Petals yellow. 



Po& about twice as long as broad, 5-12 mm. long. 

 Pods glabroiis or nearly so. 



Leaves not stellate, glabrous, except the cUiatemargin. (Depauperate 

 variety of) il. D. streptocarpa. 



Leaves more or less stellate over the whole surface. ' 



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



midrib weak. 16. D. alpina. 



Leaves Unear-oblanceolate, scarcely ciliate; midrib strong. 



17. X). 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. ventTOsa. 

 Leaves sparingly long-hairy or glabrate above. 



22. D. soboUfera. 

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



wide, 3-5 mm. long. 

 Leaves oblong to linear; mid vein strong. 



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



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



Plant densely pulvinate; leaves oblong or linear-oblong, 



less than 5 mm. long, densely imbricate. 



24. D. andina. 

 Leaves obovate, thick; mid vein indistinct. 



25. D. uncinalis. 

 Pod globose. 26. D. sphaerocarpa. 



Leaves glabrous except the unbranched ciUations 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. pectinaia. 

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



29. D. Nelsonii. 

 Petals white. 



Leaves finely stellate. 



Leaves luiear 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. lanchocarpa. 

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



Leaves hirsute-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. high, 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. 



Plajits glabrous, except the margins of the leaves, which are occasionally ciU- 

 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. D. graminea. 



