406 Transactions. — Botany. 



found a young prothallium which was quite colourless save 

 for a faint yellow tinge at the upper end, as well as two 

 others, still without sexual organs, which showed only scanty 

 chloroplasts. It is quite probable that on the germination of 

 the spore the tubercle is first formed, and when this is at too 

 great a depth in the soil to receive any light it will doubtless 

 be colourless. But I have never observed any fully developed 

 prothallium that was not green above, whilst all prothallia 

 which had succeeded in producing an embryo had reached the 

 surface and attained a considerable development of chloro- 

 phyll. 



A comparison of the prothallium of Phylloglossum with 

 those of the few species of Lycopodium in which the gameto- 

 phyte is known shows that it is distinctly of a Lvcopod 

 type. But, as is well known, there is a remarkable diversity 

 amongst the prothallia of the different species of Lycopodium. 

 On the whole, the prothallium of Phylloglossum nrobablv 

 resembles a prothallium of the L. cemuum type more closely 

 than any other, though it is quite without the leaf-like assimi- 

 latory lobes of L. cemuum. Perhaps we are justified in 

 regarding it as the simplest known type amongst the iso- 

 sporous Lycopodince. 



The general simplicity of the structure of the prothallium 

 of Phylloglossum seems to favour the view that it is a primi- 

 tive form of lvcopod. It is, of course, recognised that Phyllo- 

 glossum is a permanent embryonic form, but the simplicity of 

 structure of the mature sporophyte does not necessarily prove 

 that it is a primitive form of the lycopodiaceous phylum. 

 Bower has expressed the view that Phylloglossum is probably 

 a reduced form, and the absence of transitions between the 

 simple cylindrical pointed protophylls and the scale-like 

 sporophylls, so like those of some species of Lycojjodiuru, may 

 favour this view, if we regard these structures as homologous. 

 Some observations which appear to be new may throw some 

 light upon this question. Bower states that Phylloglossum 

 has been seen branched. I am able to say that branching 

 occurs in at least two distinct ways : — 



1. The spike or strobilus occasionally branches ; perhaps 

 one strobilus in two thousand will be found forked, the two 

 divisions becoming equally developed. I am, of course, only 

 speaking of the form which grows in New Zealand, and this 

 may possibly be a slightly more robust form than that found 

 in Australia. The branching usually takes place above the 

 lowest sporophyll, sometimes quite at the base of the spike, 

 near the lowest leaf, sometimes further up, or even close to 

 the apex of the strobilus. 



But even when the strobilus forks there is no transition of 

 form between the sporophyll and protophyll. I have occasion- 



