HoLLOAVAY. — Studies in the New Zealand Species of Lycopodiurn. 201 



liave previonsl}- described (16, v>\). 271-73), sliOMnng the two equally developed 

 cylindrical branches inclined to one another at an acute angle, tlie point of 

 the angle being the first-formed part of the prothallus. The usual fungal 

 zones extend up the outside of the two branches, while their opposed faces, 

 which are in point of fact the upper surfaces of the branches, consist of the 

 empty large-celled parenchyma. There is a very marked groove at the 

 extreme end of each branch, where the meristem is situated. This lies 

 somewhat towards the inner side, so that the antheridia, which are present 

 in large numbers, extend partly down the inner side of the arms. I have 

 not up to the present been able to trace the next stages in the growth of the 

 prothallus from this branched form, but enough has been said to show 

 that it constitutes a very interesting modification of the usual compact 

 saucer-shaped form, and possibly provides a transition between it and the 

 branched epiphytic type in which the meristem is confined to the ends of 

 the branches. One other variation from the normal must be described. 

 1 sectioned a fairly young prothallus of the saucer form, which showed 

 absolutely no fimgal infection or difterentiation of its tissues into zones. 

 The narrow outer layer of cells around the outer portion of the prothallus 

 had collapsed, but I could see no traces of fungus in the collapsed cells. 

 The rest of the prothallus consisted of quite uniform large cells of the usual 

 parenchyma form. There was an abundant development of antheridia 

 around the entire lip. I cannot now tell whether the prothallus was situated 

 at the surface of the ground or not. It is, of course, possible that the whole 

 of the fungal zones had been eaten away uniformly by an insect while the 

 prothallus was still growing. The fact that the inner boundary of the 

 palisade layer in this type of prothallus is always exceedingly well marked 

 and even lends itself to such an ex])lanation. I considerecl this peculiar 

 instance worthy of record, not in order to include it here as a striking 

 example of the plasticity of the L. fastigiatum prothallus, but so that it 

 might be compared with any other instance of a fungusless Lycopodiurn 

 [)rothallus, should such ever be found. 



The other type of prothallus in this section is that of L. complanatum 

 and of the New Zealand species L. scariosmn. The following details of 

 the structure of the former will be given, so that a comparison may be 

 instituted with the New Zealand species. The prothallus is more or less 

 carrot-shaped in form, with its lower region tapering even when fully grown, 

 .so that the zones of tissue in the vegetative region are much narrower than 

 they are in the prothallus of the clavatum type. However, as a result 

 of its greater length these tissues about equal in amount those of the latter 

 type. The central core of cells is narrow, and the cells themselves are 

 poor in contents and are elongated in the direction of the prothallus axis. 

 The palisade tissue consists of very narrow, much-elongated cells, which 

 .show their greatest length in the thickest part of the prothallus. This 

 zone, which is only one cell deep, serves as a store for reserve substances, 

 there being no store tissue corresponding to that which is found in 

 L. clavatum. In the lower region of the prothallus the palisade cells are 

 empty, but higher up they are full. The fungal hyphae are found only 

 in the cell-walls of this zone, and they sometimes form between the cells 

 large oval spheromes. There is the usual fungal cortical tissue. This 

 prothallus sometimes produces one or more secondary prothalli as shoots 

 on the primary prothallus. 



With regard to the prothallus of L. scariosum, Miss Edgerley says that 

 the palisade layer is several cells wide ; but I find that, whereas in sections 



