Plate VII. 



CORN-HORSETAIL {Equisetum ar-ueme). 



1, Fertile Shoots 



a. Spike bearing sporophylls 



b. Younger spike, enlarged 



c. Cross-section through spike 



d. Sporophylls 



f. Sporangia (closed) 



f. Sporangia (open) 



2. Vegetative Shoot 



g. Spores 



h. Spores, enlarged, with four elaters, 



opea and closed 

 /', Leaf-sheath 

 k. Ring 

 m. Horizontal rhizome 



