COLOE CHARACTER. 39 



study of these plants ; so great is tlie Aveight \vLich changea- 

 bility of color carries with it as a character in this tribe* 

 Again : Aplopappus and Clirysopis^ are distinguished from 

 Erig(3ron by color of flowers alone. In the last the rays are 

 not yellow, and the yellow of the disk changes to purple. In 

 both the preceding all the flowers are permanently yellow ; 

 and this is all. In a word, the former are homochromous, the 

 latter like Aster is heterochromous. And many an excellent 

 botanist, in dealinj^j with dried specimens of new species, has 

 placed one or more of his novelties in a wrong genus, through 

 a wrong guess as to the color of the flowers. A considerable 

 list could be made up from the synonomy of Asteroide.^, of 

 species which were by such mistake at first published in Asier 

 or some other such genus, and afterwards transferred to the 

 proper homochromous genus, upon the discovery of the fact 

 that their rays were yellow. Although the color character is 

 not even here absolute, one hazards nothing in asserting that 

 to abandon it as no longer one of the fundamental principles 

 of classification in this vast tribe of plants, would be to plunge 

 the whole tribe into phytographic chaos- 



Althoufdi the Linn^ean pronouncement against color is a 

 general one, there are other organs besides the flowers, m 

 relation to which it is even more generally and more success- 

 fully employed in the diagnosis of species. And here, too, 

 Linnreus, notwithstanding his adverse aphorism, in practice 

 leads the way. Take the genus Salix for an illustration. In 

 it he names S. vitdUna and piirimrea in reference to the 

 widely and constantly different color of the bark upon the 

 branchlets ; S. fusca because of a dark shade of color apper- 

 taiuing to the upper surface of the foliage and to the catkins ; 

 S- glanca, cmerca and alha each in allusion to a particular 

 shade of green in the foliage. Names of this kind are plenti- 

 ful throughout the whole Linuit^an nomenclature of common 

 trees and shrubs, and have been taken into use in every case, 



1 



The.e are distincraishable from each other by no absolute character, 



and are merged in one by M. Baillou. 



