30 



The seeds of the castor bean are obovoid, flattened somewhat 

 and are irregularly splotched with black or brown, a character- 

 istic appearance of this seed. 



PART III. 



CHARACTERISTICS AND IDENTIFICATION OF WEED 

 SEEDS AND MISCELLANEOUS PRODUCTS. 



CORN COCKLE. 



{Agroslemma Githago, L.) 



This seed is very often found and is objectionable on account 

 of the poisonous substance, sapotoxin, which it contains. The seed 

 is roughly kidney shaped (Fig. 22) resembling, as Winton aptly 



Figure 22 

 Fig. 22. Corn Cockle, (b) Cross section of epidermal layers and starch 

 masses. 



puts it, a rolled up caterpiller. In size it measures from 2 — 4 

 m.m. through its greatest diameter, and in color varies from a 

 deep brownish black to a dead black. The surface of the seed 

 is covered with many sinuous folds which to the naked eye seem 

 arranged in parallel rows, especially along the top of the seed. 

 Under the microscope these rows are seen to be made up of a 

 series of convolutions of the outer epidermis. One glance through 



