iqS 



GYMNOSPERMS 



Fujii,"'' who has made an extensive study of abnormalities in 

 Ginkgo, found microsporangia growing on foliage leaves. They were 

 usually near the base of the leaf blade. 



Fig. 213. — Ginkgo biloba: A, topography of strobilus, showing sporogenous tissue 

 (dotted) and mucilage cavity in the hump (outHned); B, early stage in development of 

 microsporangium, showing two of the primary wall cells and two of the primary sporog- 

 enous cells; C, the hump, with its mucilage Cavity; A , September 2, X 20; B, beginning 

 of sporogenous tissue, X48S; C, X485. — After Dr. Anna M. Starr."* 



In the northern part of the United States the male strobili can be 

 recognized early in July as small papillae in the axils of bracts. Be- 



