Edgeeley. — Prothallia of Three New Zealand Lycopods. 



101 



Internal Structure. 



The general arrangement of tissues in L. scariosum is like that of 

 L. volubile, or still more that of L. clavatum ; but a striking point in 

 which L. scariosum differs from both is in the small proportion of its cells 



Fig. 18. — Section of prothallium of L. scariosum, showing 

 proportion of cells occupied by the fungus. 



occupied by the fungus hyphae. A glance at figs. 18 and 19 will show 

 that the tissue infected by the fungus occupies only something like a 

 quarter or a fifth of the whole prothallium, while in L. volubile and also 

 in L. clavatum it occupies half. Fig. 18 shows that the tissue infected by 

 the fungus extends also, in parts, to the lobes of the upper surface. 



Fig. 19. — Section of lower part of prothallium of L. scariosum. 

 a, limiting layer ; b, c, and d, the layers occupied by the 

 fungus ; e, storage layer. X 80. 



The tissues of the prothallium of L. scariosum are, — 



(a.) A limiting layer o. elongated cells, from some of which rhizoids 

 spring. These rhizoids may be merely prolongations of an epidermal cell 

 or may be cut off from a basal cell by a cell-wall. They show the presence 

 of fungus hyphae inside their cavities. 



