200 



TransactiorifS. 



magnified view of the lower portion of the conical region of this particular 

 prothallus is given in fig. 10, in which the remains of the original spore can 

 be seen still attached to the basal cell of the cone. Whether or not a 

 filament ever is formed from the germinating spore, as is known to occur 

 in the prothallus of Tmesipteris, cannot be here stated. The presence 

 of the fungus in these basal cells serves to keep the latter from collapsing 

 for a considerable period, and if a filament is ever formed in the epiphytic 

 Lycopodium prothalli one would expect that, as in the case of Tmesipteris, 

 it would not easily be lost. It is clear, at any rate, from fig. 10 that in some 

 cases at least the germinating spore gives rise immediately to the cone- 

 shaped tissue body. "In his description of the prothalli of L. Selago and 

 L. complanatum Bruchmann figures a single cell at the basal point of the 

 prothallus. 



Main Body of the ProtJiallus. 



The main body of the prothallus consists essentially of two regions, 

 the hinder vegetative and the forward generative region. There is no 

 such differentiation in structure in the fungus-bearing tissues of the central 



Fig. 12. — L. Billardien var. gracile. Transverse section of basal cone of mature 

 prothallus, snowing fimgus throughout, also first branch in longitudinal 

 section . x 108. 



Fig. 13. — L. Billardieri var. gracile. Transverse section of mature prothallus above 

 basal cone, showdng initial development of the central strand. X 108. 



body of this prothallus as is found in those of the clavatum and complanatum 

 types. In these latter prothalli the fungal tissues are clearly marked 

 off into cortical and palisade zones, and in the case of the New Zealand 

 species L. voluhile and L.fastigiatum there is also a wide and very character- 

 istic zone in which the fungal hyphae are also intercellular. The particular 

 type of structure found in these deeply-growing terrestrial types can be 

 put in connection with the general habit of growth of the prothallus. 

 This is the opinion expressed by Bruchmann in his description of the 

 prothalli of L. clavatum, L. annotinum, and L. complanatum (1, pp. 18, 58). 

 As will be seen below, even the prothalli of the Cernua section have attained 

 to a certain degree of differentiation in their fungus-bearing regions. The 

 fungus-infested cells in the main prothallfal body of the three New 

 Zealand species which belong to the Phlegmaria type are all practically 

 similar to one another in their form and contents. In longitudinal section 

 it is apparent that transverse divisions have taken place in them so that 



