502 



WEED FLORA OF IOWA 



False Calais (Agoseris cuspidata (Pursh.) Steud.). 



Achenes fusiform, slightly contracted at the apex, with 10 

 prominent ribs ; one-half in. long, or little longer ; pappus of soft, 

 white, capillary bristles ; scar at base, whitish, with a small opening. 



Orange Hawkweed (Hieracium aurantiacum L.). 



Achene oblong, columnar, one-tenth in. long; blackish or dark 

 brown, marked with prominent longitudinal ridges, minutely 

 roughened ; base of achene with small circular raised border, lighter 

 than remainder of achene; pappus of numerous somewhat brown- 

 ish bristles, frequently breaking away near the top of the achene, 

 then showing short bristles. 



Fig. 382A1 



Fig. 382B 



Fig. 382A 



Fig. 382. Seeds of Hawkweeds. A and Al, Orange Hawkweed (.Hieracium 



aurantiacum) . B, Hawkweed (Hieracium, canadense) . 



(A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; Al, drawing by L. R. Collins ; 



B, drawing by Charlotte M. King.) 



Hawkweed (Hieracium canadense Mx.). 



Achenes one-tenth to one-eighth in. long, oblong, columnar, 

 10-15-ribbed ; blackish or reddish ; base with prominent disklike 

 area marked by circular ring; apex with somewhat fine tawny- 

 colored capillary bristles; below point of attachment is an area 

 bulging outward; capillary bristles have tendency to break. 



