332 



THE PTERIDOPHYTES 



bodies (Fig. 288) generally 



FIG. 288. Gametophytes and 

 young sporophy tes of a club moss 

 (Lycopodium complanatum) 



A, gametophyte with young sporo- 

 phyte : /, tissue filled with the fila- 

 ments of a fungus situated just 

 outside a layer of palisade cells. 



B, the fungus-infected tissue. C, 

 a young club moss still attached 

 to the subterranean gametophyte. 

 A, B, from material of Bruch- 

 mann prepared by Miss Lyon ; 



C, after Bruchmann 



subterranean and practically desti- 

 tute of chlorophyll, like those of 

 the moonwort and adder's-tongue. 

 They are therefore saprophytic,and 

 associated with them are fungal 

 filaments to form a mycorrhizal 

 relation (Sec. 278). The sexual 

 organs are sunken structures. 

 The sperms are two-ciliate. 



The embryo sporophyte remains 

 attached to the gametophyte by a 

 large foot (Fig. 288) for a long 

 time after the stem and root are 

 developed, and must obtain much 

 nourishment from the gameto- 

 phyte, as in the case of the ferns. 



323. Selaginella. Sclaginclla 

 is readily distinguished from Lyco- 

 podium. The leaves in most 

 species are arranged in four rows, 

 two rows of smaller leaves on the 

 upper surface and two rows of 

 larger leaves somewhat at the sides 

 (Fig. 289, A). The cones also have 

 four rows of spore leaves (sporo- 

 phylls) and are consequently four- 

 angled. The spores are of two 

 sizes, and the type is perhaps the 

 best illustration of heterospory in 

 the pteridophytes. Forms of Sel- 

 aginella are frequently called 

 " little club mosses," for many of 

 them are much more delicate than 

 the lycopods. But some tropical 

 species, frequently cultivated in 



