THE GENERAL CHARACTERS OF SEEDS 



445 



Wild Turnip (Brassica campestris L.). 



Seeds generally nearly spherical or oblong; the caulicle and 

 radicle usually conspicuous along the middle, one-twentieth to one- 

 twelfth in. in diameter, cultivated forms larger, roughened and 



o O 



Fig. 294. "Wild Turnip (Brassica campestris). A and B, various forms of 

 seeds. C, a seed in cross section showing' cotyledons and caulicle. D, the 

 embryo. E, seeds, natural size. 



(After Hillman, Bull. Mich. Agr. Exp. Sta.) 



more finely ridged than in B. nigra and B. arvensis; color grayish 

 or brownish; scar at one end. With clover and grass seed. 



Rape (Brassica napus L.). 



Seed nearly spherical or sometimes oblong, one-fourteenth to one- 

 twelfth in. in length, prominently reticulated; closely resembles 

 B. arvensis. Found in mustard and clover seed. 



o 



• 



Figure 295 B 

 B. Black Mustard (Brassica nigra). A, 



Figure 295 A 



Fig. 295. A. Rape (Brassica napus) 



seed enlarged, showing the surface network of dark lines. B, a group of 



seeds, natural size. 

 (A, drawings by Ada Hayden ; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) 



Black Mustard (Brassica nigra (L.) Koch.). 



Seed nearly spherical, more generally broadly oblong, one-twen- 

 tieth to one-fifteenth in. in diameter; surface marked with fine 

 ridges; frequently whitish scar at one end; embryo as in B. 



