THE GENERAL CHARACTERS OF SEEDS 



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Figure 325A 



Figure 325B 



Figure 325C Figure 325D 



Pig. 325. A. Swamp Milkweed (Asclepias incarnata). B. Common Milkweed 

 (Asclepias syriaca). a, b, different views of seed; c, cross section; d, e, 

 natural size. C. Butterfly Weed (Asclepias tuberosa). D. Whorled 

 Milkweed (Asclepias verticillata) . 

 (A, drawing by L. R. Collins; B, after Hillman ; C, D, by C. M. King.) 



Butterfly Weed (Asclepias tuberosa L.). 



Seed ovate or eliptical, three-tenths in. in length ; surface rough- 

 ened by ridges on both back and inner faces; winged margin, 

 lighter brown than middle part of seed ; raphe marked by a distinct 

 ridge; coma fine, silky, smooth. 



Whorled Milkweed (Asclepias verticillata L.). 



Seeds ovate, one-sixth in. in length, margin distinct, lighter in 

 color than the rest of the reddish brown seed; surface veined, but 

 not ridged or roughened; raphe a distinct ridge on inner face; 

 coma soft, silky ; very smooth. 



CONVOLVULACEAE, CONVOLVULUS FAMILY. 

 Common Morning-glory (I pomoea purpurea (L.) Roth.). 



Seed dark brown, with one convex side opposite to 2 flattened 

 faces meeting at an angle, length 5 mm., width 4 mm. at the base 

 of the seed; at lower end of the angle between the two flattened 

 faces is the scar, also dark brown ; surface dull, finely roughened. 



Small Bindweed (Convolvulus arvensis L.). 



Seeds large, oval, one side convex, the other side with a broad 

 ridge ; one-sixth in. long, a depression at one extremity representing 

 the scar ; surface of seed roughened, dark brown in color ; embryo 

 large, surrounded by the fleshy endosperm. Found in cereal grains. 



