OBSERVATIONS ON THE COMPOSITE. 107 



Eriocarpum. Its various species have been distributed 

 partly to ^^Aplopappiis^' and partly to Aster, according as 

 the rays were found to be xanthic or cyanic. The habit of 

 this genus is well marked, but it embraces perennial and 

 annual species. Its character is precisely that which dis- 

 tinguishes Sericocarpits from AsieVy and much like that by 

 which Brachychceta is separated from SoUdago. Or again; 

 it is separable from all its near allies Just as Acamptopappus 

 from the shrubby ^^Aplopappiy The character is a densely 

 silky, mostly short and turbinate achene, with pappus of 

 exceedingly unequal usually short and somewhat flattened 

 awn-like barbellate bristles, which, in their maturity, in most 

 of the species (perhaps in all) are inclined to spread away 

 somev/hat radiately around summit of the achene. To these 

 characteristics it is to be added that both pappus and indu- 

 ment of achene are permanently white, or at least, nearly 

 white. 



With these good characters of fruit, an almost constantly 

 hemispherical involucre, and peculiarly spinulose-toothed 

 foliage, the genus is thoroughly acceptable; and not the 

 less so as adding another to the list of those in this tribe in 

 which, as in Lessingiay Pentachceta and Erigeron^ some 

 species have yellow, others purple ray-flowers. The cyanic 

 species bring the genus near to MachceranUiera; and 

 Nuttall had even some of the xanthic ones in his Dieteria, 

 a synonym of Machmranthera. 



In the following arrangement of the species of Erio- 

 CARPUM, the yellow-rayed group holds the first place, for the 

 reason that those nearest to Nuttall's type are homochro- 

 mous, though that type itself is rayless. 



* Bays when present yellow. 



-^Perennial or siiffridescent species, 



1. E. GRiNDELioiDES, Nutt Trans. Am. Phil. Soc. vii. 321 

 (1840). Aplopappns Nidtallii, Torr. & Gray, FL ii. 242 

 (1842). Aster Niittallii, O. Ktze. Eev. Gen. 318 (1891) 



J 



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