A SEED KEY TO COMMON WEEDS 385 



11. <Jroove not extending entire length of 

 seed, quite flattened, pointed at one 



end Lepidium ruderale L. 38 



10. Without a distinct groove on the faces. 

 11. Seed coat loosely fitting or wrinkled, 

 brick red, angles very distinct and 

 acute (fig. XII) . .Oenothera biennis L. 59 

 11. Seed coat not noticeably wrinkled, 

 angles more rounded. 

 12. Not black when ripe, usually flesh- 

 colored and granular 



Cuscuta arvensis Beyrich 65 



12. Black when fully ripe. 



13. Surface reticulated 



Plantago major L. 77 



13. Surface not reticulated 



Plantago Rugelii Dene. 78 



9. Not markedly angled, quite regular in 

 shape. 

 10. Almost round, both faces concave, a 

 slight notch at one edge, the opposite 



edge thicker Malva sp. 56-57 



11. Dark reddish brown usually under 



2 mm. in diameter 



Malva rotundifolia L. 56 



11. Light grayish in color, usually over 



2 mm. in diameter 



Malva moschata L. 57 



10. Not round, with both faces concave as 

 above. 

 11. With a distinct longitudinal groove 

 starting at the narrow end of the 

 seed and extending at least one-half 

 length of seed. 

 12. Surface finely dotted or pitted, dis- 

 tinctly gray-brown, somewhat 

 shiny; inserted here as a check 



(fig. XXXIX) 



Barbarea vulgaris R. Br. 42 



12. Surface not finely dotted or pitted. 

 13. Groove extending entire length of 

 the seed and running on the end, 



broader 



Sisymbrium officinale Scop. 41 



13. Groove not extending entire 

 * length of seed. 

 14. Groove double or looped, under 



1.2 mm. long (fig. XL) 



Capsella Bursa-pastoris A. Medic. 39 



25 



