1920 



HA UPT—FOSSOMBRONIA 



322 



of his obscurity in explaining the situation, the development of 

 the antheridium would be as represented in fig. 1. 



Investigation 



Thallus 



The vegetative body of Fossombronia cristula is minute, being 

 only 2-4 mm. in length. It is creeping and semi-prostrate, although 



5 



-2 



Fig. 1. — Above, F. longisela; below, F. cristula 



the stem tips may occasionally be more or less ascending. The 

 branching is rather profuse and is strictly apical. The stem shows 

 no indication of a conducting system as in Pallavicinia and Sym- 

 phyogyna. The plants form dense matlike growths over the sub- 

 stratum, and are attached by means of long, violet-red rhizoids 

 (fig. 6) . The plant is an annual, developing in the early summer 

 as soon as its habitat becomes sufficiently dry; in the Dune Park 

 region the spores are ripe by late September or early October. 



