89 



OBSERVATIONS ON THE COMPOSIT.E.— YI. 



By Edward L. Greene, 



[Chrysopsis continued, from p. 76]. 



There is one other type, still received as of this genus, 

 which were perhaps more consistently removed from it; I 

 refer to O. pilosa, Nutt., a not well known member of the 

 Arkansas flora. The plant is annual, rather tall and coarse, 

 and with more likeness to Heterotheca than to true Chrysop- 

 sis. Its involucral bracts are so nearly equal as to give a 



El 



The 



palesB of the outer pappus are very conspicuous, and some- 

 what erose. The achenes are so distinctly ten-ribbed— at 

 least those of the ray— that the ribs are manifest even 

 through the somewhat dense pubescence. These are the 

 characters of a genus, apparently. The living plants I have 

 not seen. 



The geographic range of Chrysopsis is somewhat pecu- 

 liar. The species are, in a manner, dispersed over a con- 

 siderable part of the North American continent, but in 

 general only along the lines of the mountain elevations, or 

 between these and the seaboard. They are absent from the 

 level interior parts of the continent, and also from the higher 

 latitudes. None occur in the great prairie and low forest 

 regions of the middle Mississippi and its tributaries. They 

 are likewise wanting on the desert plains of the Great Basin, 



though not absent from the mountain districts adjacent to 

 such plains. 



There are two groups of species, quite separate in their 

 respective geographic ranges, and with corresponding organ- 

 ographic differences. One of these is of the Appalachian 

 Mountain system, with members dispersed from eastern 

 Massachusetts to Mexico. The other has for its center 

 of distribution the Rocky Mountain region. One of its 

 species runs eastward over the high plains quite to the verge 

 of the prairies, northward into British America, and west- 



Eeythea, Vol. II., No. 6, [1 June, 1894]. 



