B.oi.J.ovf AY .— Studies in the New Zealand Species of Lycopodium. 237 



Zealand species already dealt witli. In these two types the cone form is 

 at once initiated and is continued throughout the life of the prothallus. 

 There is no extension in length comparable even to that of the Cernua and 

 Inundata types, although, as I mentioned in a former paper (7, p. 273) and 

 hope to describe more fully in a later one, the young prothallus of L. fasti- 

 g latum branches after it has passed through the initial cone stage. It assumes 

 the shape of the letter " Y," the arms of the prothallus being true branches, 

 as indicated by the fact that in each of them there is a central core of fungus- 

 free cells completely surrounded by the fungal zone, the meristem being 

 located near, bub not actually at, the apex of each arm. Although the 

 • mature prothallus in this species has the saucer form, yet it frequently 

 bears evidence of this early branching. The prothalli of these two types 

 have departed altogether from the self -nourishing, chlorophyllous habit, 

 and have become wholly dependent upon the symbiotic fungus, although 

 the prothallus of L. volubile is able to develop chlorophyll if it happens to 

 grow at the surface of the ground. We find that the external tissues in the 

 whole of the vegetative portion of the prothallus have been given over to 

 the fungal inhabitant, so that in form this vegetative region is one large 

 regularly-shaped cone. The prothalli of the clavatum and com.'planatum 

 types, owing to their terrestrial habit, occur in soil of a nature different 

 from that of the humus-growing, epiphytic prothalli. There seems to be no 

 need for the prothallus to elongate or branch in order to come in contact 

 with a sufficient supply of food, although, judging from the branching by 

 which the young prothallus of L. fastigiatum assumes the saucer form, it 

 could do so if necessary. The fact that these types of prothalli are so 

 much larger in size than the surface-growing form of L. Selago is obviously 

 due to the much greater degree of dependence upon them of the young 

 plant than in the latter species. They function largely as storehouses, 

 the large quantities of starch and oil which they contain having been noted 

 by all who have described them. 



The compact, massive form of the prothallus in L. ramulosum, L. laterale, 

 and L. cernuum must not be compared too closely with that of L. Selago 

 or of the terrestrial subterranean types, for the position of the meristem 

 in the latter is altogether different from that in the former. Nor can 

 the elongated form of L. ramulosum be compared exactly with that of 

 L. Billardieri. It would seem, however, that the difference between the 

 marginal meristem of the Selago prothallus and the apical meristem of 

 the epiphytic types is not so great. The prothalli of Jboth these types 

 invariably begin with the cone form, and the subsequent manner of growth 

 of each, and the form which the meristem takes, can be explained quite 

 naturally (as I have attempted to do earlier in this paper) as resulting 

 simply from the position of the prothallus in the soil. That there is a 

 somewhat close relationship between these two types appears also from 

 the fact of their similarity in the embryo plant and in the presence of para- 

 physes. The clavatum and complanatum types of prothallus also seem 

 to be allied to that of the Selago tjrpe, possessing the same kind of marginal 

 meristem, although they lack paraphyses. Moreover, the embryo plant of 

 these deeply subterranean forms differs from that of L. Selago only in the 

 abnormal development of the " foot," a character which has quite obviously 

 resulted from their position in the soil. 



The prothalli of the Cernua and Inundata sections seem to stand rather 

 apart from the rest of the genus. The meristem is of a quite different 

 nature, the fungal habit has not been adopted to the same extent, the 

 filamentous manner of growth is largely present, and the form of the 



