THE GENERAL CHARACTERS OF SEEDS 475 



Ribgrass, Buckhorn (Plantago lanceolata L.). 



Seeds oblong, convex on back, one-twelfth to one-seventh in. in 

 length, edges folded inwardly to deep central longitudinal groove 



Fig. 344. Buckhorn (Plantago lanceolata). A and B, group of seeds showing 

 both the convex and grooved faces. C, a sterile seed. D, a seed in cross 

 section. E, seed showing the mucilage. F, the natural size. 

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



on inner face; brown, smooth, shining; scar at center of groove 

 frequently of dark color. 



Dooryard Plantain (Plantago major L.). 



Seeds oblong to trapezoidal in shape, usually 4-sided, some of 

 them 3-sided, one-twenty-second to one-sixteenth in. long; brown- 

 ish to black ; surface bearing 5 ridges radiating from scar ; scar on 

 middle of inner face, often with white markings. 



Rugel's Plantain (Plantago rugelii Dene.). 



Seeds oblong, rhomboidal, generally trapezoidal with flattened 

 edges, one-eighteenth to one-twelfth in. in length ; color brownish to 

 black ; surface minutely roughened, ridgelike markings absent ; scar 

 circular, whitish. 



