72 CALIFORNIA ACADEMY OF SCIENCES. 



differs in its indehiscent pods, on short reflexed pedicels, 

 and its dissimilar habit. 



H. unilateralis. 



Hirsute-pubescent with branching hairs: leaves obovate, 

 with cuneate base | — 1 inch long, sparingly toothed toward 

 the apex : branches from a few inches to more than two feet 

 long, spreading horizontally, flowering and fruiting through- 

 out their entire length: pods 2 lines long, 1% lines wide, 

 with some stout, straight bristles besides the stellate pubes- 

 cence, in maturity twisted: pedicels hardly a line long, stout 

 and deflexed. Draba unilateralis, M. E. Jones, Bull. Tori*. 

 Club, IX. 124. 



Abundant in certain localities from Colusa County, Cali- 

 fornia, southward to the peninsula, where it was first collect- 

 ed by Mr. Jones in 1882. It is especially common in the 

 wheat lands of the lower San Joaquin Valley, as well as still 

 farther northward. 



The long, wiry, nearly prostrate branches, with their 

 pods all turned downwards, the valves of the latter break- 

 ing anywhere else more readily than along what should be 

 the natural line of dehiscence, forbid our thinking of the 

 plant as congeneric with even the annual species of Draba. 



ATHYSANUS. Nov. Gen. Cruciferarum. 



Sepals equal. Petals small or none. Style very short. Sili- 

 cle orbicular, not margined, indehiscent, flat, nerveless, 1- 

 celled, 1-seeded. Cotyledons accumbent. Annual, leafy at 

 base, strongly resembling the preceding genus: branches 

 slender, erect-spreading or trailing, racemose; their nu- 

 merous pods hanging earthwards on short filiform pedicels. 



A. pusillus. 



Herb of about half the size of Heterodraba, but with the 

 same habit, foliage and pubescence, save that the leaves are 



