HoLLOWAT. — Studies in the New Zealand Species of Lycopodiuni. 1(35 



plant the natural position in the genus to be assigned to any pai-ticular 

 species. 



The facts brought forward in this paper concerning the varieties of the 

 New Zealand species and their range of varialiility will tlius have a double 

 significance : they will provide new inaterial for the study of the question 

 as to whether or not epharmonic adaptations ever do become fixed and 

 hereditary; and they will help to indicate the natural relationships which 

 exist between the different sections of the genus, and between the individual 

 species which are included within those sections. 



Species belonging to the Sections Selago and Phlegmaria. 

 Hahit and External Form of Plant, and Nature of Strobilus. 



It has long been recognized that as regards habit and external form 

 these two sections are closely connected. The type species L. Selago and 

 L. Phlegmaria are, of course, very distinct, the former being a short, upright, 

 little-branched terrestrial form in which there is no differentiation between 

 fertile and sterile leaves, the fertile zones alternating up and down the 

 stems with sterile zones, and the latter being a much-elongated, pendulous, 

 much-branched epiphyte in which there is a special sporophyll formation, 

 the sporophylls being characteristically confined to the ends of the branches 

 and the latter appearing as narrow whipcord-shaped strobili. But between 

 these two extreme forms there are numerous species illustrating every grade 

 of transition. The species which are grouped by both Baker and Pritzel 

 under the heading Suhselago possess the sporangia aggregated into quite 

 easily recognizable terminal spikes which approach the Phlegmaria condi- 

 tion, although the transition from sterile to fertile leaves and from sterile 

 to fertile regions of the stem in these species is very gradual. Also, included 

 in both subsections Euselago and Subselago of Pritzel's Selago section are 

 pendulous epiphytes and upright terrestrial forms, although on the whole 

 there is seen to be a gradual transition in the section from the erect terres- 

 trial form to the hanging epiphyte, this transition keeping pace with the 

 transition in the fertile region from the Selago condition to the Phlegmaria, 

 condition. Again, in the Phlegmaria section are grouped forms some of 

 which are robust and upright in growth, and others tender and pendulous ; 

 and of these the former possess short thick strobili in which the sporophylls 

 show a more or less gradual transition from the sterile leaves, and the latter 

 possess in some cases very distinct long whipcord-like strobili, while in 

 others the fertile leaves may be not different from the sterile leaves. The 

 New Zealand species which belong to these two sections present some very 

 interesting transitions of this nature, which will be instanced. 



It will be at once apparent that a classification which is based upon one 

 character alone — as, e.g., the nature of the fertile region — is bound to be 

 unsatisfactory. The general habit of the Lycopodivm plant and its external 

 form must be considered along with the nature of the fertile region, for 

 these three characters are closely interdependent. That these two sections 

 together constitute a natural division of the genus seems to be suggested 

 by the fact that they show certain common growth-features which are 

 markedly absent from the remaining sections. In habit they are consistently 

 orthotropic, so that their extent of growth is strictly limited. As a result 

 of this orthotropic manner of growth it is found that throughout the two 

 sections the roots are confined to the basal region of the plant, as many as 

 six or seven roots appearing in the cortex of the stem in a transverse section 



