THE HOMOSPOROUS LEPTOSPORANGIAT1E 



387 



dies as in other Ferns. Sclerenchyma is largely developed, 

 especially in the petioles, where the whole mass of ground tissue 

 in Lygodium (Fig. 224) is composed of this tissue. 



In one section of Aneimia the stele (Fig. 223) has the form 

 of a continuous tube with both external and internal phloem 

 and endodermis (see also Boodle (2) ). 



The leaves are pinnate in all the forms except a few species 

 of Schizaa. Lygodium, as is well known, shows a continuous 

 growth at the apex of the leaf, something like Gleichenia, but 

 here the primary apex retains its meristematic condition, and 

 the extremely long and slender axis of the leaf twines about its 

 support like the stem of many climbing plants. The sporo- 



A. 



13. 



FIG. 225. Aneimia hirsuta. A, Sporophyll, showing the two fertile pinnae, sp.; B, 

 segment of the fertile pinna, enlarged; C, D, sporangia, X about 40. 



phylls are usually smaller than the sterile leaves, or where only 

 portions of the leaf are sporiferous these are much contracted. 

 The anatomy of the leaf corresponds closely with that of the 

 other Ferns. The stomata, which are for the most part con- 

 fined to the lower side of the leaf, are always arranged in two 

 parallel rows in Schisaa, and the peculiar stomata of Aneimia 

 have already been mentioned. The trichomes are for the most 

 part hairs. Only in Mohria do scales occur. 



In Schizcea pusilla the sterile leaves are filiform, without 



