224 



MOSSES AND FERNS 



CHAP. 



The male inflorescence of the Polytrichaceae is especially 

 conspicuous, as the leaves immediately surrounding the anther- 

 idia are different both in form and colour from those of the 

 stem. They are broad and membranaceous, and more or less 

 distinctly reddish in colour. A well-known peculiarity of 

 these forms is the fact that the growth of the stem is not 

 stopped by the formation of antheridia, but after the latter have 

 all been formed the axis resumes its growth and assumes the 

 character of an ordinary leafy shoot. This, of course, indi- 

 cates that, unlike most of the ■ Mosses, the apical cell does not 

 become transformed into an antheridium, and the researches of 



Fig. 122. — Dawsonia superba. A, Transverse section of the stem, X3S; B, part of the 

 central cylinder, showing water-conducting elements, t, X200; C, outer tissues 

 of the stem, X200. 



Hofmeister (2), Leitgeb (9), and Goebel (7) have shown 

 that this is the case. The antheridia form groups at the base 

 of each leaf of the inflorescence, and Leitgeb thinks it probable 

 that each group represents a branch, i. e., the inflorescence is a 

 compound structure, and not directly comparable to the simple 

 male inflorescence of Funaria. The sporogonium in Poly- 

 trichum has a large intercellular space between the inner spore- 

 sac and columella as well as the one outside the outer spore-sac. 

 In both cases the space is traversed by the conferva-like green 

 filaments found in the other stegocarpous Mosses. The apoph- 

 ysis is well developed, especially in Polytrichum, and the 



