Plate VII. 



CORN-HORSETAIL (Equisetum ar-vense) . 



1. Fertile Shoots 



a. Spike bearing sporophylls g. Spores 



b. Younger spike, enlarged h. Spores, enlarged, with four elaters, 



c. Cross-section through spike open and closed 



d. Sporophylls i. Leaf-sheath 



e. Sporangia (closed) i. Ring 



f. Sporangia (open) m. Horizontal rhizome 



2. Vegetative Shoot 



