THE GENERAL CHARACTERS OF SEEDS 



425 



III 



Figure 258A 



A 



^b 



c#ft( 



Figure 25SB 



Fig. 258. A. Hemp {Cannabis sativa). I. Seed in envelope. II. Seed withoul 



envelope. III. Cross section of seed. F. pericarp ; S. testa ; B. endosperm. 

 B. Nettle (Urtica gracilis), a, seed in envelope; b, seed enlarged; d, natural 



size. 

 (A, after TVinton ; B, after Hillman. Bull. Mich. Agr. Exp. Sta.) 



Nettle (Urtica gracilis Ait.). 



The fruit enclosed in membranous calyx ; seed pale straw-color, 

 1 mm. long, flattened, ovate, slightly pointed toward the ends, 

 smooth ; point of attachment at broader end. 



POLYGONACEAE, BUCKWHEAT FAMILY. 



Sour Dock (Rumex ocetosa L.). 



Inner sepals of calyx in fruit, with wings; achene convex be- 

 tween angles ; one-twelfth in. in length, variable, smooth, shining ; 

 dark reddish brown. Probably occurs in European grown clover 

 seed. 



Sheep Sorrel {Eumex acetoscUa L.). 



Calyx usually persistent, not wing-margined in fruit, roughened, 

 with prominent veins; closely fitting achene, elliptical or ovate 



