292 CONTKIBUTIONS FROM THE NATIONAL HERBARIUM. 



Flowers rose-colored; whole plant rou<;lily 

 stellate-pubescent. 



Base of the stems woody and branched. 9. ^1. perennans. 

 Base of the stems herbaceous or 



nearly so, simple 10. ,4. sparsljloni. 



Radical leaves entire or merely denticulate. 

 Pods reflexed. 



Pubescence densely and linely stellate, 



whitish; pods 2 mm. wide 12. ^1. jxibcntla. 



Pubescence scant, stellate, or wanting; 



pods 3 to 5 mm. wide 13. ^4. sujf'rutescens. 



Pods not reflexed. 



Pods divaricate; herbage .soft pubescent 



with stellate hairs 11. ^4. holanderi. 



Pods ascending. 



Plant glaucous ; lower leaves finely and 



densely stellate-pubescent 14. .4 lafifolia. 



Plant green ; pubescence scanty. 



Stems several, slender, from a 



woody caudex; leaves small 17. A. inlaophyUa. 



Stems solitary or few from a her- 

 baceous or scarcely woody base. 

 Tall 30 to 60 cm. ; plant some- 

 what glaucous; pubescence 



of 2-forked hairs 15. ^4. dninniiondn. 



Low 10 to 30 cm.; plant glab- 

 rous or somewhat stellate 

 pubescent below 16. ^4. lyallii. 



1. Arabis lyrata occidentalis S. Wats, in Gray, Syn. Fl. 1': 159. 1895. 



Type locality: "From Alaska to British Columbia and the eastern side of the Kocky 

 Mts. in Brit. America; Point Pelee on Lake Erie, Macoun." 

 Range: Alaska to Washington and eastward to Lake Erie. 

 Specimens examined: "On Nooksack River near Mount Baker," Suksdorf 1999. 

 Zonal distribution: Iludsonian. 



2. Arabis whitedii Piper, Bull. Torr. Club 28: 39. 1901. 

 Type locality: Wenache, Washington. Collected by Whited. 

 Range: Eastern Washington. 



Specimens examined: Wenache, WMfed 1057; Cral) and Wilson creeks, Sandhenj cfc 

 Leiberg 275. 



Zonal distribution: Upper Sonoran. 



Mature specimens collected by Whited, May 19, 1905, show the ripe pods to be nearly 

 erect, 17 to 20 mm. long, finely and densely stellate-pubescent, and nearly always longer 

 than the divergent pedicels with which they form a pronounced angle; seeds wingless, in a 

 single row; cotyledons accumbent. It may be a biennial. 



This species is not closely related to any other, in my opinion, but is to be associated 

 perhaps with A. nuttallii Robinson. 



3. Arabis nuttallii Robinson in Gray, Syn. Fl. 1': 160. 1895. 

 Arabis spathulata Nutt.; Torr. & Gr. Fl. 1: 81. 1838, not DC. 1821. 



Type locality: "Lofty dry hills of the Platte, from the Black Mountains to the central 

 chain." 



Range; Washington to Montana and Nevada. 



