37 



The seed coat of persicaria differs somewhat from those of 

 others of this family, the surface la^-er being found in well cleared 

 specimens to have irregular rows of dark dots which are in the 

 middle of the irregular polygonal cells. It is difficult to clear 

 sufficient h' to get more details of the cell structure, but this 

 characteristic is sufficient to identify the seed. (Fig. 30.) 



HARE'S EAR. 



{Couringia orientalis.) 



In size this seed is from 1.5 — 2.5 m.m. long and about 1.5 

 inches in diameter. It is roughly egg shaped w^th a somewhat 



Figui-e 31 

 Fig. 31. Hare's Ear. 



depressed pointed end, and a more or less pronounced ridge along 

 the back of the seed and a slight depression on the ventral side. 

 In color it varies from light to dark browm, with a grejdsh tinge 

 sometimes not noticeable. The surface is covered with very small 

 projections which give a slightly roughened appearance to the 

 surface. Under the hand lens these projections appear to be in 

 more or less parallel rows. (Fig. 31) 



PEPPER GRASS. 



{Lepidium Virffinicum, L.) 



This seed is small, flattened and ham-shaped, of a rusty brown 

 color and in size from 1 — 2 m.m. in length and from .5 — 1 m.m. 

 in width. Along the edge of the seed is usually found a thin pro- 



