Bui. 88, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



Plate IV. 



Fig. 1.— Involucres of Rabinal Cotton, Showing Connate and Appressed 



Margins. 



(Natural size. ) 



FiQ. 2.— Open Involucres of Egyptian Cotton. 

 (Natural .■^ize.) 



