Hollow AY. — St tidies in the New Zealand Species of Lycopodium. 201 



they are more equidimensional than are the adjacent cells (fig. 11). It is 

 rather the centrally-placed, fungus-free cells which have become changed 

 in form. They are always considerably elongated, and are somewhat 

 narrower than the cells of the fungal zones (fig. 11). This is, of course, 

 quite in accordance with the function of translocation which they are 

 called upon to perform in these elongated prothalli. Certain of the 

 epidermal cells grow out as rhizoids, a transverse wall separating the 

 rhizoid proper from its parent cell. The width of the fungal zone in the 

 main prothallus body varies in different parts, but, generally speaking, 

 it diminishes towards the growing region. However, if lateral branches 

 are borne well forward on the prothallus the fungus will be foimd well 

 forward also. The fungus is always massed around the base of a branch, 

 but in those portions of the main body which lie in between the branches 



[vsntTal] 



Fig. 14. — L. Billardieri. Transverse section of the prothallus shown in fig. 3, at the 



point c. X 60. 

 Fig. 15. — L. Billardieri. Transverse section of the prothallus shown in fig. 5, at the 



point a. Compare also fig. 2, c. x 60. 

 Fig. 16. — L. Billardieri. Transverse section of the prothallus shown in fig. 3, at the 



point a. X 135. 



the fungal zone may be no more than one or two cells in width. In the 

 basal cone-like region the cells, which are all equidimensional, are all 

 infested with the fungus, there being here no centrally-placed conducting 

 strand. At the actual base of the prothallus even the epidermal cells show 

 the presence of the fungus (fig. 10). Fig. 12 is a transverse section of the 

 basal cone, showing the first-formed lateral branch in longitudinal section. 

 It will be seen that in the central region in this figure the fungus is inter- 

 cellular as well as within the cell-cavities, and the cells here consequently 

 appear roundish in shape. Farther forward still the centrally-placed cells 

 are free from fungus and represent the beginning of the conducting-strand 

 (fig. 13). Fig. 14 is a transverse section of the prothallus which is shown in 

 fig. 3 taken at the point marked c. In this region of the main body the 

 fungus has extended forward so that it underlies the old antheridia. The 

 rhizoids are here ventrally borne, and the fungus is aggregated along the 

 ventral side so that the prothallus shows a dorsiventral structure. Fig. 15 



