Hohhow AY .- —Studies in tht New Zealand Species of Lycopodium. 213 



which the saprophytic condition is still subordinate to the chlorophyll 

 condition must be regarded as a primitive feature. Included in these two 

 sections are several forms of strobilar formation. In L. contextum and 

 L. cruentum it represents a near approach to the undifferentiated SeJago 

 condition, and this may be regarded, along with the dichotomous branching 

 of the stem and the chlorophyllus nature of the prothallus, as an indication of 

 the ancient character of the Inundata-Cernua group. The long, erect, club-like 

 pedicelled strobili, and the short unpedicelled numerous strobili borne at 

 the tips of all the branches, both occur in this group, as also in the Clavata 

 section. Possibly these two types represent Extreme modifications, and, 

 seeing that thev both occur in the one species. L. fastigiatiim, it is probable 

 that they do not indicate any phylogenetie differences between the species. 



The protocorm condition in the young plant has been found in all those 

 species of the Inundata and Cerrnia sections whose embryogeny is known, but 

 it has never been found in any other section of the genus. Treub considered 

 that he had found an indication of this organ in the embryo plant of L. Phleg- 

 maria, but this has never been established. The protocorm is thus a dis- 

 tinguishing character of the Inundata-Cernua division of the genus, and is 

 always associated with the surface-growing chlorophyllous prothallus of the 

 L. cernuum type. The monotypic genus PhijUoglossvm is also characterized 

 by the possession of a protocorm, and Thomas has shown (29) that its pro- 

 thallus is of the L. cernuum type. Treub elaborated the theory that the 

 Lgcopodium protocorm is an exceedingly primitive organ, and Phylloglossum 

 came to be regarded as the most primitive of vascular plants. However. 

 Bower and Goebel have both doubted that it represents a primitive condition 

 in the phylogeny of vascular plants, regarding it rather as a physiological 

 adaptation. In my accounts of this organ as it occurs in L. laterale, L. ramu- 

 losum, and L. cermmm (16) 1 have concluded on the one hand that it is a 

 ph^^siological development, but that on the other hand, occurring as it does 

 throughout the whole Inundata-Cernua division, and being always associated 

 with a type of prothallus which is regarded as little modified from the 

 ancestral type, it must certainly be considered as primitive for this division. 

 Further, the fact that Goebel has described adventitious protocorms in 

 L. inundatum (14), and that I have also found them in L. ramulosnm (17), 

 would seem to indicate that this organ is not to be regarded on a par 

 with the seedling " foot " as an adaptation which has altogether been 

 governed by the nature of the prothallus with which it is associated, 

 but that it is part of the inherited constitution of this division of the 

 genus. 



The prothallus in this group is always chlorophyllous and surface- 

 growing, but it is remarkably variable in form, the different forms possibly 

 resulting from the different depths at which the spores germinate. In 

 L. cernuum and L. laterale the " shaft " may be somewhat elongated or 

 almost suppressed, in the latter case the prothallus appearing more compact 

 and massive in form. Very extreme forms are met with in L. ramulosum. 

 Here the short form is relatively exceedingly massive and very much like 

 a young prothallus of the claratum type in external appearance, almost 

 the whole of the bulk of the prothallus, except for the actual crown, con- 

 sisting of opac^ue fungal tissues. The elongated form may show as many as 

 five distinct fungal swellings along its length, each swelling being usually 

 associated with a local group of assimilating lobes and sexual organs. 

 This long-drawn-out form may also branch. The prothallus of L. salakense 

 is also much elongated. 



