52 



THE FERN BULLETIN 



like ; sporangia borne on the under side of the leaves 

 or on simple or branched sporangiophores ; euspor- 

 angiate or leptosporangiate ; sporophylls not forming- 

 cones. Gametophvte comparatively large, tuber-like 

 w ithout chlorophyll and subterranean, or developed as 

 a flat, simple or branched thallus, hermaphrodite or 

 unisexual ; spermatozoids multiciliate. 



Equiseteae. Horsetails. 25 species. 



Sporophyte perennial, herbaceous, with a rhizome, 

 and with jointed, mostly hollow, simple or branched, 

 aerial stems which are either annual or perennial ; vas- 

 cular bundles in a circle ; leaves reduced to sheaths 

 around the joints, the sheaths toothed; sporangia 

 borne on small peltate sporophylls arranged in whorls 

 on a terminal cone ; eusporangiate ; spores with four 

 narrow, strap-like, hygroscopic appendages. Game- 

 tophyte a small green thallus, usually unisexual ; sper- 

 matozoids multiciliate. 



Lycopodieae. Lycopods. 155 species. 



Sporophyte perennial, herbaceous, with or without 

 a rhizome, the aerial stems upright or trailing; branch- 

 ing monopodial or dichotomous ; leaves small, without 

 a ligule, scattered on the stem, into two to many ranks ; 

 sporangia solitary on the upper surface of the leives 

 or in their axils, eusporangiate; sporophylls in bands 

 alternating with the sterile leaves or arranged in spirals 

 in terminal cones; spores small, not appendaged. 

 Gametophyte small, sometimes subterranean, with or 

 without chlorophyll, hermaphrodite; spermatozoids 

 biciliate. 



V. PTERIDOPHYTA HETEROSPORAE. 



( \ LAM ARIEAE. Fossil. 



Paleozoic plants, sometimes of tree-like aspect and 

 dimensions, with hollow-jointed stems with a circle of 



