(i7i) 



Family Cruciferae. 

 Cardamine -pratcnsis august i folia Hook. Near mouth of 

 Bonanza and mouth of Klondike (Williams). 



Roripa Williamsii Britton, sp. now 



Glabrous, about 1.5 dm. high. Leaves about 5 cm. Ion-;-, 

 deeply pinnatilid into oblong, obtuse, entire or toothed seg- 

 ments 2-3 mm. wide, the terminal segment much larger than 

 the lateral ones; racemes elongating and with very distant 

 pedicels in fruit; pedicels spreading, about 1 cm. long; pod 

 oblong, obtuse, about 3 mm. long. 



Near mouth of Bonanza Creek, R. S. Williams, June 18, 

 1899. 



Arabis lyrata occidental is S. Wats. Near mouth of Bo- 

 nanza (Williams). 



Arabis Hulbocllii Hornem. White Horse Rapids (Tarle- 

 ton). 



Parrya macrocarfta R. Br. The Dome, Klondike-Indian 

 Divide (Tarleton). 



Erysimum cheiranthoidcs L. Dawson (Williams). 



Erysimum angustatum Rydb., sp. nov. 



A more or less cespitose perennial, with a slender tap-root 

 and short branched rootstock or caudex. Stems 1-2 dm. 

 high, sparingly grayish strigose, obtusely angled; leaves 

 very narrowly oblanceolate-linear or linear, 4-7 cm. long, 

 1-2 mm. wide, grayish strigose; sepals linear, obtuse, about 

 8 mm. long, two alternate ones deeply saccate at the base, 

 pale yellowish; petals lemon-yellow, about 14 mm. long; 

 pods 5-8 cm. long, about 1.5 mm. broad, obtusely angled, 

 ascending on ascending pedicels 5-8 mm. long, with a dis- 

 tinct beak 3-5 mm. long, somewhat constricted between the 

 seeds ; cotyledons incumbent. 



This species is probably nearest related to E. as-perimum 

 (Cheiranthus asferrimas Greene) but differs in the more 

 elongated branches of the caudex or rootstock, which are 

 covered with remnants of old leaves, the narrower perfectly 

 entire leaves, the more slender stem, the less sharply angled 

 pod and the more evident beak. The type was collected at 

 Dawson by R. S. Williams, July 13, 1899. 



