THE GENERAL CHARACTERS OF SEEDS 



471 



Figure 339A Figure 339B 



3*13. 339. A. Self-heal {Prunella vulgaris). A, a group of seeds, enlarged, the 

 lower left-hand one with the scar-appendage broken away ; the upper left- 

 hand one showing the outer face. B, a group showing the natural size ; C, 

 a longitudinal section of a seed, showing the embryo. 



Ia Motherwort (Leonurus cardiaca). a and b, different views of seed, c, seed, 



natural size. 



(After Hillman, A, Bull. Nev. Agr. Exp. Sta. ; B, Bull. Mich. Agr. Exp. Sta.) 



SOLANACEAE, NIGHTSHADE FAMILY. 



Horse Nettle (Solanum carolinense L.). 



Berry orange-yellow, 1.6 to 2 cm. in diameter; seeds pale dull 

 yellow, much flattened, obovate, 2 to 3 mm. in length ; finely granu- 

 lar, or indented over whole surface. 



Black Nightshade (Solanum nigrum L„). 



Berries black, globular, smooth; seed asymmetrically ovate, flat- 

 tened, pale yellowish brown, finely granular; diameter about 

 1.5 mm. 



Buffalo Bur (Solatium rostratum Dunal.). 



Black berry enclosed in spiny yellow calyx ; seeds nearly circular, 

 bearing a dent on one side of the margin; flattened, pitted on the 

 surface; both sides irregularly indented with depressions; color, 

 dull dark brown; seed about 2.5 mm. broad. 



Jimson Weed (Datura stramonium L.). 



Seed one-eighth in. in length, brownish or blackish, kidney-shaped, 

 elliptical or nearly spherical, with numerous large depressions and 

 smaller pits; hilum with a small depression. 



