I40 MOSSES AND FERNS chap. 



dispersal are already multicellular. Apparently no germ tube 

 is formed, but the spores develop at once into a cell mass upon 

 which, while still very young, the mucilage clefts are developed, 

 and at an early stage the infection by the Nostoc cells is 

 effected. The growth of the older capsule and gradual develop- 

 ment of the spores are the same as in Anthoceros. 



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

 it was largely upon the results of his investigations upon this 

 plant that Leitgeb ^ based his theory of the close relationship of 

 the Anthocetoteae and Jungermanniaceae, 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 species, 

 N. orbicularis {valvatd), 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. - 



The thallus much resembles a small Anthoceros, and sections 

 through it show that in its growth and the development and 

 structure of the sexual organs there is close correspondence. 

 The thallus contains very large lacunse, which are formed in 

 pretty regular acropetal order, and vertical sections show these 

 large cavities increasing regularly in size as they recede from 

 the apex. Similar but less regular lacunae occur in A. fusiforinis. 

 The antheridia arise as in Anthoceros, endogenously. The 

 youngest stage found is shown in Fig. 68, A. Here evidently 

 the young antheridia ( c? ) have been formed by the longitudinal 

 division of a single hypodermal cell, whose sister epidermal 

 cell has divided again by a transverse wall to form the outer 

 wall of the antheridial cavity (Figs. A, B). The commonest 

 number of antheridia formed is four. 



Less regularity is found in the next divisions than in 

 Anthoceros, although in the main they are the same. This is 

 observable both in longitudinal and cross-sections (see Fig. 68, 

 D). The full-grown antheridium is more flattened than in 

 either species of Anthoceros examined by me, and the stalk 

 shorter and thicker, but otherwise closely resembles it, although 

 the extremely symmetrical arrangement of the cells, especially 

 of the wall, is much less noticeable. 



The archegonia correspond very closely, both in position 



1 Leitgeb (7), vol. v. p. 39. 



