THE HOMOSPOROUS LEPTOSPORANGIATAi 



373 



of some of the larger Mosses, c. g., species of Mniiuii. Hooker 

 ( I ) reduces them all to three genera, which, however, are often 

 further divided. Of these Loxsoma is represented by but one 

 species, L. Cunninghamii, a form which seems to be intermedi- 

 ate in general characters between the Cyatheacese and the other 

 Hymenophyllace?e, but its life history and anatomy are not 

 known. Of the other genera Hooker gives seventy-one species 

 to Hymenophylhim and seventy-eight to Trichomanes.^ 



The GametopJiyte 



The gametophyte is known more or less completely in sev- 

 eral species of both Trichomanes and Hymenophylhim. The 



Fig. 214. — Trichomanes Draytonianum. Germination of the spores, X52S; r, primary 



rhizoid. 



large spores germinate promptly, but their subsequent develop- 

 ment is very slow. They contain chlorophyll and often begin 

 to germinate within the sporangium, where they may often be 

 found divided into three equal cells by w^alls radiating from the 

 centre (Fig. 214). All of the cells begin to grow out into 

 filaments, but usually only one of them develops into the pro- 

 thallium, the others dividing only once or twice, and forming 

 short brown rhizoids. In some species of Trichomanes, e. g. 



*The number of species known now considerably exceeds this. 



