— 1 13 — 



transferred to some other genus than the one in which 

 it was described. 



Since there are no hard and fast lines for distinguish- 

 ing species, our so-called species are largely matters of 

 opinion, and in the arrangement of the list I have been 

 guided by the principles laid down in my paper entitled 

 " Species and Varieties Among the Ferns/'' recently pub- 

 lished in The Fern Bulletin. The geographical dis- 

 tribution of the species and forms has been brought up 

 to date and the distribution outside of our limits has also 

 been added. It is hoped that the tables of classes, orders, 

 etc., may be useful as an aid to fixing the relationships of 

 the various groups in the minds of young students. 



Main Groups of the Ferxs axd Ferx Allies. 



SERIES I. — FERXS. Spores minute, alike in size, 

 borne on the backs of broad leaf -like fronds or occa- 

 sionally in berry-like spikes. 



Order i. — Prothallium subterranean, pale; vernation 

 of the fronds straight or inclined. Eusporangiate. 

 Ophioglossales. 



Order 2. — Prothallium terrestrial or epiphytic, green ; 

 vernation of the fronds circinate. Leptosporangiate. 

 Filicales. 



SERIES II— FERX ALLIES. Spores minute, alike 

 in size or of two sizes, one much larger than the other, 

 borne usually in the axils of the leaves. Plants of vary- 

 ing aspect ; leaves not fern-like. 



Order 3. — Spores of two sizes borne in sporocarps. 

 Water plants rooting in mud or floating on the surface 

 of still water. Salvtniales. 



Order 4. — Spores all alike, borne on the under side of 

 peltate scales assembled in cone-like catkins. Plants 

 usually of moist places ; leaves scale-like, stems hollow. 

 Equisetales. 



Order 5. — Spores of one size (in Lycopodiaceae) or 

 of two sizes (in Selaginellaceae) borne in the axils of 

 scale-like leaves usually forming cones. Plants of dry 



