CHAPTER XII. THE PTERIDOPHYTA. 345 



inner base of ihe outer peristome, and is itself segmented or 

 toothed at the lop. See Fig. 554. 

 There are three subdivisions : 



(a) The Acrocarpi have erect stems and bear the fructifica- 

 tion at the apex. To this group belong the Phascums, Dicrani- 

 ums, Leucobryums, Funarias, Bartramias, Bryums, and many 

 other common Mosses. 



(b) The Cladocarpi bear their fruits on short lateral branches. 

 They are aquatic Mosses, and include but two genera, Fontinalis 

 and Dichelyma. 



(c) The Pleurocarpi bear the fruit laterally in the leaf-axils, 

 either of the main stem or on the branches. They include the 

 Leptodons, Neckeras, Fabronias, Climaciums, Hypnums, and 

 several other genera. 



CHAPTER XII. 



SERIES III.— THE PTERIDOPHYTA, OR VASCULAR 

 CRYPTOGAMS. 



Principal Division-. 

 I. Equisetineae. 



i 



r 



Psilotaceae 



II. Filicinese > Filices 



Rhizocarpeae. 

 Lycopodiaceae. 



III. Lycopodineas I 



I Ligulat*. ... Selagmelle*. 

 ^ ** \ Isoeteae. 



The Pteridophyta, like the preceding series, consist entirely 

 of chlorophyll-bearing plants, which are never either parasitic 

 or saprophytic. The word " Pteridophyta " literally means " fern- 

 plants," the Ferns being the most numerous as well as the most 

 important members of the Series. 



The term "Vascular Cryptogams " is applied because here, 

 for the first time, we find a distinct development of ducts and 

 other vessels which are the result of cell-fusions. In many of 

 the species, in fact, we find a differentiation of tissues almost as 

 complete as that found in flowering-plants. Moreover, in the 

 plant-body all the organs of vegetation, root, stem, leaf and 

 plant-hair or trichome, are fully represented. 



