148 



MOSSES AND FERNS 



CHAP. 



dermis of the mature sporophyte, which otherwise closely 

 resembles that of Anthoceros. 



The spores may remain undivided, as in Anthoceros, or in 

 some species, c. g., D. crispus, they become multicellular before 

 they are discharged. In this respect these species of Dcndro- 

 ceros recall Conoccphahis and PcUia, where germination begins 

 before the spores are set free. 



Notothylas 



The third genus, Notothylas, is of especial interest, because 

 it was largely upon the results of his investigations upon this 



Fig. 79. — Dciidroccros Brcutclii- A, section of young spororhyte, X2S0; B, section of 

 mature sporophyte showing spores and elater-like, sterile cells; C, single elater, 

 X 250. 



plant that Leitgeb ( (7), v., p. 39) based his theory of the close 

 relationship of the Anthocerotes and Jungermanniales. All 

 of Leitgeb' s observations on the young capsule were made from 

 herbarium material, and, as he himself admits, were in all cases 

 embryos that had not fully developed. The writer has made 

 a very complete examination of the commonest American spe- 

 cies, A^. orbicularis (z'ahata), and the results of the study of the 

 development of the sporogonium differ so much from those of 

 Leitgeb that they will be given somewhat in detail. Mottier 



