THE GENERAL CHARACTERS OF SEEDS 



477 



COMPOSITAE, COMPOSITE FAMILY. 



Baldwin's Ironweed (Vemonia baldwini Torr.). 



Achenes practically indistinguishable from those of the follow- 

 ing species. 



Figure 347A 

 Fig. 347. Ironweed seeds 



A. Vemonia fasciculata. 

 Achenes with pappus. 

 (Drawings Charlotte M. King.) 



Figure 347B 

 Vernonia baldwini. 



Ironweed ( Vernonia fasciculata Mx . ) . 



Achenes 3-3.5 mm. long, and 1 mm. broad; general form slender, 

 cylindrical, often slightly curved ; strongly 9-10-ribbed, ribs of 

 same color as achene, pale brown ; tuft of purplish brown pappus 

 bristles attached at larger end; length of pappus hairs 6 mm. 



White Snakeroot {Eupatorium urticaefolium Eeichard). 



Achene long, 5-angled, prominently grooved between the angles 

 oue-twelfth to one-tenth inch; generally blackish except at the 

 base where it is yellowish ; the scar at base with a small circular 

 opening, and whitish border; smoothish (see figure), pappus of fine 

 white capillary bristles; the upper part of beak expanded into 

 candelabra form, bearing thp somewhat fragile pappus. 



Joe-Pye Weed {Eupatorium purpureum L.). 



Achenes smooth, prominently ribbed ; 5-angled, truncate ; about 

 one-eighth of an inch long; base white; pappus with numerous 

 tawny-colored, capillary bristles. Miss Mary Nichols, who studied 

 the achenial hairs of E. villosum, finds that they are short with 

 lateral canals. The achenial hairs of E. purpureum, according 

 to Mr. Fracker, are simple, in E. villosum duplex. 



