I*LATR Vll. 



CORN-HORSETAIL (Equisetum ar-vense). 



1. FERTILE SHOOTS 



a. Spike bearing sporophylls 



b. Younger spike, enlarged 



c. Cross-section through spike 



d. Sporophylls 



e. Sporangia (closed) 

 f. Sporangia (open) 



2. VEGETATIVE SHOOT 



g. Spores 



h. Spores, enlarged, with four elaters. 



open and closed 

 /'. Leaf-sheath 

 k. Ring 

 m. Horizontal rhizome 



