THE GENERAL CHARACTERS OF SEEDS 



499 



Dandelion (Taraxacum officinale Weber). 



Achenes two-fifths in. long including persistent beak, fusiform in 

 shape, prominent ribs, and projecting teeth at ribs, especially at 

 upper end ; beak four-fifths to one in. in length ; achenes light gray in 

 color, otherwise like preceding; pappus capillary, whitish, fragile. 

 With grass seeds. 



Field Sow Thistle (Sonchus arvensis L.). 

 Achenes dark reddish brown, duU, ends slightly truncate, length 

 2.5-3 mm., width 0.8 mm., somewhat flattened, with 4 strong ribs or 

 angles, between which lie smaller ridges ; numerous transverse ridges 

 on the ribs. 



B A 



Fig. 3780 



Fig. 378. Seeds of Sow Thistles. A. Field or Perennial Sow Thistle (Sonchus 



arvensis) ; B, natural size, showing pappus on one acUenc. 



B. Sonchus oleraceus, different views of achenes. 



C. SoncTviis asper, A and B, different views of acliene?, C, ac!-enes, natural size. 



(After Hillman, Bull. Mich. Agr.- E.Kp. Sta.) 



Spiny Sow Thistle {Sonchus asper Vill.). 



Achenes broadly oblcng or lance-sliaped, similar faces, many- 

 fibbed, one-tenth in. long, slightly pubescent, prominent ridges 

 minutely roughened; base with a minute sear, brownish; the apex 

 with projecting point and iine, capillary, white, bristles. Found 

 with grass seeds. 



