292 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



FlowiM-s rose-t'olored ; whole plant roughly 

 stollato-pubescent. 



Base of the stems woody and branched. 9. A . ]>ereimans. 

 Base of the stems herbaceous or 



nearly so, simple. 10. .1. N/mrsi flora. 



Radical leaves entire or merely denticulate. 

 Pods reflexed. 



Pulx^scence densely and finely stellate, 



whitish; pods 2 mm. wide 12. A. puberula. 



Pubescence scant, stellate, or wanting; 



pods 3 to 5 mm. w^ide VS. A. suffrutescens. 



Pods not refle.xed. 



Pods divaricate; herbage soft pubescent 



with stellate hairs 11.^. holanderi. 



Pods ascending. 



Plant glaucous; lower leaves finely and 



denseh- stellate-puln'scent 14. .4 latifolia. 



Plant green; pubescence scanty. 



Stems several, slender, from a 



woody caudex; leaves small .. . \7. A. juicrophylla. 

 Stems solitary or few from a her- 

 baceous or scarcely woody base. 

 Tall ;i() to (K) cm. ; plant some- 

 what glaucous; puln'scence 



of 2-forke(l hairs 15. A. drmnniondii. 



Low 10 to 30 cm.; plant glal)- 

 rous or somewhat stellate 

 pulx!8cent below 1(5. A. lyallii. 



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



Tyi'e UK.'ALiTi': "From Alaska to British Columbia and the eastern side of the Rocky 

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

 Range: Ala.ska to Washington and eastward to Lake F>ie. 

 Specimens examined: "On Nooksack River near Mount Baker," Suksdoif 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, Whited 1057; Crab and Wilson creeks, Sandhenj & 

 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. V: 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." 



Rangs; Washington to Montana and Nevada. 



