236 Transactions. 



best be described as a radially-built filament. The immediate effect of the 

 presence of the fungus also can be clearly seen in the prothalli of this species. 

 It almost invariably causes a swelling of the tissues of the prothallus at 

 the infection spot, this swelling being due to the greater or less develop- 

 ment of the intertial fungal tissue in which the hyphae are intercellular. 

 Sometimes the fungus is restricted to one place "in the prothallus, this 

 being towards or at its base, so that there is present a basal swelling. But 

 in all three New Zealand species which belong to the cernuum type, and 

 more especially in L. ramulosum, more than one distinct fungal area is 

 frequently formed. Another form sometimes adopted by the prothallus 

 of L. ramulosum, and to be seen also in those of L. laterale and L. cernuum, 

 is that in which the usual shaft is practically, absent, the crown of lobes 

 immediately surmounting the basal fungal region. The latter is then 

 more bulky than usual, the whole mature prothallus bearing more truly 

 the cone form than is normally the case in the prothalli of these sections. 

 That this particular massive form is not a fixed character appears from 

 the fact that only infrequently are these bulky prothalli of regular shape 

 and growth. However, just as the long-drawn-out, more filamentous 

 form may bear some comparison with the epiphytic, elongated type, so 

 may the massive form be compared with the deep-growing clavatum and 

 complmiatum types, and the prothallus of L. ramulosum is thus seen to 

 possess as great significance as that of L. Selago in bearing witness to the 

 plasticity of the Lycopodium prothallus. 



When we turn to the epiphytic type of prothallus we find that there 

 also the form of the prothallus must be considered along with the nature 

 of the fungus-distribution in its tissues. The whole of the basal cone con- 

 stitutes, as it were, a primary turbercle which contains the fungal element 

 throughout its tissues, being comparable to the first-formed tubercle in 

 L. cernuum, when that is there present. The elongated, cylindrical regions 

 of the epiphytic prothalli, have completely passed out of the cone form, 

 nor do they show any localized swellings induced by the presence of 

 the fungus. The fungus is distributed throughout the branches and the 

 vegetative region of the central body, and the absence of swelling is 

 pro'bably due to the rapid elongation of the prothallus in all its parts. 

 Even the discontinuous infection which is to be seen often in the branches 

 does not result in any swelling of the tissues as it does in L. ramulosum. 

 Thus, although the elongated prothalli of L. ramulosum may be compared 

 with the epiphytic type, yet they never attain to the characteristic form 

 or structure of the latter. It will suffice here to allude quite briefly to 

 the statement made by certain other writers, notably Lang, that this 

 difference is probably merely the expression of the fact that in the Cernua 

 and Inundata types fungal assimilation has not assumed the same degree 

 of importance in the life of the prothallus as it has in the epiphytic types, 

 for the prothallus is surface-growing and never gives up its chlorophyllous, 

 self-nourishing habit. The epiphytic prothalli, however, live in soil of a 

 different nature, and have adopted a wholly subterranean mode of life, in 

 which they depend altogether upon the activities of the fungus for their 

 nourishment. This has been the immediate cause of their extensive 

 ramifications and their character of continuous cylindrical growth. In this 

 respect, therefore, they are to be regarded as more specialized than the 

 chlorophyllous type. 



Althoiigh I have not in the present paper given any description of the 

 prothalli of the species L. volubile, L. fastigiatum, and L. scariosum, which 

 belong to the clavatum and complanatum types, yet it is appropriate here 

 to compare briefly their form and structure with that of the other New 



