182 Transactions. 



below, the prothallus of the latter is peculiar. Cheeseman (9, p. 250) states 

 that L. ramidosum " is more closely allied to the Australian L. cliff usum 

 than to any other species, principally differing, as Mr. Baker has remarked, 

 in its entirely terminal spikes, whereas in L. diffusum they are frequently 

 lateral." It would seem, then, natural to place these three species very 

 close together in the same section, and not to dissociate them, as both 

 Baker and Pritzel in different ways have done. When growing on sphag- 

 num bogs throughout Westland, where it is associated with Gleichenia 

 cdpina and Cladium teretifolium, the plants are closely intermatted, and 

 their rhizomes penetrate the peaty soil in all directions. The aerial branches, 

 by reason of the close nature of the vegetation which covers the ground. 

 are more or less erect. When it is growing amongst thicker vegetation 

 on a hillside I have often observed that L. ramidosum occurs in dense, 

 mossy cushions, the intermatted aerial branches in these cases being particu- 

 larly well developed and drawn out. On wet soil on which there is a very 

 scanty mossy covering individual plants of this species assume a habit in 

 which the branches are closely pressed to the surface, the cones alone 

 standing erect, almost pedicelled. In this case the rosette form of the 

 plant, produced by the continued dichotomies of the branches, is very 

 striking. The main stems show a considerable range of variability in their 

 form. They may be, in drier situations, above-groimd and green, and 

 covered with ordinary vegetative leaves, but on the bogs they function 

 as subterranean rhizomes, white in colour, with scattered scale leaves. 

 Again, the more deeply penetrating rhizomes in the latter situation are often 

 quite naked and brown in colour. L. Cockayne (10, p. 17) has made the 

 mteresting observatio-n that the cones of L. ramidosum " are absent or 

 scantily produced in shade plants, but extremely abimdant in those growing 

 in bright light." He has suggested that this is a point which would lend 

 itself well to experimental investigation. 



It is apparent, then, tiiat the habit of L. ramulosum is very variable, 

 although in its typical form on sphagnum bogs it is quite characteristic. 

 The external form of L. laterale also is in a plastic state, and the position 

 of the cones in neither species is quite fixed. Thus in res})ect of these 

 characters they are more or less closely allied, and also their affinity with 

 the Australian L. diffusum seems to be clear. 



Stem-anatomy. 



In describing the characteristic nature of the vascular tissues of L. Drum- 

 mondii I indicated that this mixed type of stele with the very extended 

 protoxylems is that also of those New Zealand species of Lycopodium which 

 belong to the section Cernua. It is very distinct from the first type 

 described in this paper, which, as I have tried to show, holds, in spite of 

 the many modifications in the external form of the plant, throughout the 

 subgenus Urosfachya, and also from the third type, which is characteristic 

 of the Clavata section. It therefore should be given prominence to, along 

 with the character of the prothallus and of the embryo plant in the sections 

 Inundata and Cernua, as a character to be taken into account in a natural 

 classification of the genus. 



In fig. 10 is shown the vascular cylinder of the main rhizome of L. cernuum. 

 It will be seen both from the amount of vascular tissue and from the scale 

 of the magnification that the stele of this species is an exceptionally large 

 one. For that reason it shows even more clearly than do the other species 

 the nature of the mixed type of structure. Both metaxylem and phloem 



