VOL. I.] Corcopsidcce and Tageiincie. 309 



by two of the following species. Heterospernnim differs from 



1 



Bidens chiefly in having wing-margined outer akencs and stylifer- 

 ous rays. Some species of Bidens also, however, have styhferous 



rays. 



Heterospermum Xanti Gray, Proc. Am. Acad., v, 162, is one 

 of the new species of the Xantus collection from Cape St. Lucas, 

 and was described from a **single specimen 6 or 7 inches high, hard- 

 ly sufficient for description." Concerning it Dr. Gray writes: " The 

 disk-achenia and indeed the whole structure, except the fertile ache- 

 nia, accord with Bidens.'' An abundance of specimens from the 

 Cape Region shows a much nearer relationship than was sup- 

 posed by Dr, Gray. It is a common plant about San Jos6 del 

 Cabo, where it grows to height of a foot and is often much branch- 

 ed. From the Cape to the highest altitudes of the interior Sierras, 

 it is not uncommon but in the mountains it is smaller and often 

 abundant enough to give a yellow tinge to the hillsides. The outer 

 broad akenes are usually smooth on the back with corky margins, 

 and a similar ridge along the ventral face, each of these three lines 

 in most cases continued into a strong awn. The breadth of the 

 wing is variable and some of the inner akenes are not rarely 

 roughened with whitish protuberances. 



At San Bartolome occur forms with somewhat broader and short- 

 er leaf-segments, which are apparently identical with Bidens Xan- 



iiana Rose. 



Bidens heterosperma Gray— at least Pringle's No. 1637— has 

 strongly three*- angled akenes, the outer much shorter, broader, 

 more or less rugose or corky, the awns absent or caducous. 



Bidens heterophylla Ort., from San Francisquito mountains^ 

 has the outer akenes more or less warty. 



The following species approaches Heterospermum by having fer- 

 tile rays and sometimes a slight thickening of the margins of their 

 akenes. It is one of the handsome plants of the summits of the 

 high mountains in the interior of the Cape Region- The finely 

 divided leaves crowded near the woody bases of the many stems, 

 contrasted with the conspicuous yellow flowers, make the clumps of 

 this species growing on the clifl^s noticeable. 



Bidens nudata. Suffrutescent, glabrous, 4-5 dm. high,^ with 

 many stems from a woody base: leaves connate and sheathing at 

 base, dissected into rather remote filiform divisions, 4-5 cm. long, 



