MUSTARD FAMILY 351 



Plant densely pulvinate; leaves linear-oblong, villons-hifipld 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, ventrosa. 

 Leaves sparingly long-hairy or glabrate above. 



22. D, sobolifera. 

 Pods sparingly pubernlent 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 nun. long. 23. D. oligospcrma. 



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 ciliations on the margins. 

 Leaves densely imbricate, short. 



Pod pubescent; mid vein of the leaves obsolete. 

 ^ ^ 27. D, sphacrula. 



Pod glabrous; midvein of the leaves prominent. 



28. D. pcctinafa. 

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



29. D. Nelsonii. 

 Petals white. 



Leaves finely stellate. 



Leaves linear or linear-oblanceolate. 



^lidrib 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 linear. 6-12 mm. long. 



Pods 6-8 mm. long, not t-v\isted. 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. 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. 



Plants glabrous, except the margins of the leaves, w^hich are occasionally cih- 



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. 



Leaves spatulate or broadly oblanceolate. thick. 40. D. crassa. 



Plant decidedly hairy. . 



Pubescence long-hirsute, with simple or slightly branched hairs. 



41. D. streplocarpa. 

 Pubescence short, mostly of stellate or branched hairs. 



Styles 1.5-2 mm. long; pods glabrous or sliglitly pubernlent. 



Pod not twisted; pubescence rather sparse or minute; stem-leaves 



usually sharply toothed. 

 Stem more or less hirsute. 42. D. spectabilis. 



Stem minutely appressed-stellate. 43. D. oxyloba. 



Pod twisted; pubescence dense and graj'ish; stem-leaves entire- 

 margined or minutely denticulate. 44. D. HeUeriana. 

 Style 1 mm. long; pods densely pubescent. 



SJem erect or nearly so. „ „ , ., ,. 



Leaves thin, the basal ones usually over 2 cm. long, the caulme 



ovate to lanceolate. 

 Petals 5 mm. or more long. 



Petals pale yellow; stem-leaves often dentate. 



45. D. luteola. 



