354 BRASSICACEAE 



coarse pubescence. D. glacialis f Hook. D. vestita Payson, more common form 

 with corymbose inflorescence and softer pubescence. Rocky places, high moun- 

 tains: Alta. — -Wyo. — -Alaska. Mont. — -Alp. Je-Jl. 



21. D. ventrosa A. Gray. Densely cespitose pulvinate perennial; leaves 

 numerous and imbricate, obovate or spatulate, 1 cm. or less long; scape 1-2 cm. 

 long, villous-stellate; petals yellow, about 5 mm. long; pod densely stellate, 4-5 

 mm. long, 4 mm. wide. High mountains: Wyo. — Utah. Mont. — Subalp. Jl-Au. 



22. D. sobolifera Rydb. A low cespitose perennial, but the leafy stolons 

 often somewhat elongate; basal leaves oblanceolate, obtuse or spatulate, 1-2 cm. 

 long and 3-4 mm. wide, thick; peduncles 3-6 cm. long, stout, rather many-flow- 

 ered; petals yellow, obovate, about 4 mm. long; pedicels in fruit 7-8 mm. long; 

 pod ovate, about 6 mm. long, 3-4 mm. wide. Alpine peaks: Utah. Subalp. — 

 Alp. Jl. 



23. D, oligosperma Hook. Cespitose perennial, profusely branched; 

 leaves 5-15 mm. long, somewhat imbricate; scape in fruit 5-10 cm. high; petals 

 yellow or whitish, 5 mm. long, broadly spatulate; pedicels ascending, 3-5 mm. 

 long; pod ovate, about 4 mm. long, 3 mm. wide. D. saximontana A. Nels. 

 Mountains and dry hills: Mack. — Utah — Calif. — Alaska. Mont. — Alp. 



24. D. andina (Nutt.) A. Nels. Cespitose-pulvinate perennial; leaves 

 basal, densely imbricate, about 5 mm. long, oblong or linear-oblong; scape 1-3 

 cm. high; petals yellow, 4-5 mm. long; fruiting pedicels ascending; pod rounded- 

 ovate, 3-3.5 mm. long, 2.5-3 mm. wide. D. glacialis § & £ Hook. D. oligo- 

 sperma andina Nutt. D. oligosperma microcarpa Blankinship. Dry hills and 

 mountains: Alta. — Wyo. — Utah — B.C. Mont. — Alp. My-Je. 



25. D. uncinalis Rydb. Small cespitose and pulvinate perennial; flower- 

 ing stems scai)iform, 2-3 cm. high, sparingly stellate; basal leaves in dense tufts, 

 thick, rounded-obovate, 3-4 mm. long, spaiingly stellate; inflorescence corymbi- 

 form, few-flowered; pod ovate, 3-4 mm. long and 3 mm. wide. Mountains: 

 Utah. Subalp.— Alp. 



26. D. sphaerocarpa Macbr. & Payson. Much branched cespitose peren- 

 nial; leaves tufted, oblong or obovate, obtuse, 4—7 mm. long, finely and densely 

 stellate, the midveins indistinct; fruiting racemes elongate; pods 8-12, globose, 

 scarcely at all flattened, ovate, stellate, 2-5 mm. long; style 1 mm. long. Granite 

 washes: Ida. 



27. D. sphaerula Macbr. & Payson. Densely pulvinate cespitose perennial; 

 leaves 2 mm. long, densely clustered and imbricate, broadly linear, acute; scape 

 slightly longer than the leaves; petals slightly longer than the sepals; fruiting 

 inflorescence corymbose; pods few, broadly lanceolate, 3 mm. long, compressed, 

 stellate; style 1 mm. long. Alpine slopes: Ida. Alp. Jl. 



28. D. pectinata (S. Wats.) Rydb. Cespitose pulvinate perennial; leaves 

 oblong, thick, 3-4 mm. long; midrib very prominent; scape 1-2 cm. long; petals 

 4 mm. long; pedicels ascending; pod 3-4 mm. long, 2-2.5 mm. wide. D. globosa 

 Payson. Dry hills and mountains: Utah — Nev. Subalp. — Alp. Jl. 



29. D. Nelsoni Macbr. & Payson. Cespitose perennial; leaves linear, 5-7 

 mm. long, 1 mm. wide or less, glabrous, except the strong marginal cilia, the 

 midvein prominent; petals yellow, twice as long as the sepals; fruiting raceme 

 elongate; pods 6-15, broadly lanceolate, 3-6 mm. long, 2-3 mm. wide, pubescent 

 with simple hairs; style about 1 mm. long. Exposed ridges: Wash. — Ida. — 

 Calif. Subalp. — Alp. Je-Au. 



30. D. lapponica Willd. Cespitose tufted perennial; basal leaves 5-15 

 mm. long; scai)e 3-7 cm. long; petals 3 mm. long, obovate, white; pedicels 2-4 

 mm. in fruit; pod oblong, 6-8 mm. long, 2 mm. wide, glabrous. Alpine-arctic 

 regions: Grecnl.^ — B.C.; Eu. Alp. 



31. D. nivalis Liljeb. Cespitose tufted perennial; leaves 5-8 mm. long, 

 densely stellate; scape 1-5 cm. long; petals white, obovate, 3 mm. long; pedicels 

 ascending; pod 6-8 mm. long, 2 mm. wide. Arctic-alpine situations: Greenl. — 

 Lab. — Utah — Alaska; Eu. Subalp. — Alp. Je-Au. 



