HoLLOWAY. — Studies in the Sew Zealand Species of Lycopodiuni. 191 



that these same characters are under the direct influence of the environ- 

 ment, even more so than in any of the other sections, and thereiore we 

 may expect to find not only variations in form and structure in the species 

 themselves, but also indications that the section itself includes more than 

 one strain. This seems to follow, for example, from the fact that there 

 are two types of prothallus, and that, in the case of two of the New Zealand 

 species, along with these types of prothallus there go two distinct types 

 both of heterophylly and of strobilus-form. 



External Form of Plant, and Nature of Strobilus. 



L. volubile has a scrambling and climbing habit, and its form and 

 structure show various modifications in accordance with this. The follow- 

 ing quotation is from an unpublished work by L. Cockayne on the Vegeta- 

 tion of New Zealand : " L. volubile is an interesting example of the transi- 

 tion of a creeping ground - plant through a winding liane, by way of a 

 scrambling plant. This plant, as a creeper, in many places extends its 

 slender, woody, stiff stems far and wide, rooting in the soil and raising 

 them unsupported for 60 cm. or so into the air. Thus a prop may be gained, 

 and, this happening, the method of climbing depends upon the nature of 

 such. If the support be twiggy the liane merely scrambles through the 

 branches, its lateral branchlets at about a right angle to the axis, the 

 sporophyll-bearing branches and the hook leaves of the stem all functioning 

 as climbing-organs, the last-named also aided by the flexuous stems. When 

 the support, however, is smooth and with few projections the stem of the 

 Lycopodimn twines strongly, gripping the support tightly." In localities 

 where this species is growing in luxuriant masses upon and amongst low 

 vegetation, one frequently sees the growing shoots standing erect and 

 unsupported to a height of as much as 3 ft. to 4 ft , the flexible ends of 

 the shoots being curved similarly to those of a hop These shoots are thus 

 able to lift themselves up in a vertical direction and so reach the lowest 

 branches of small trees. Sometimes two or even three neighbouring shoots 

 in such situations will twine tightly round each other, and so lift them- 

 selves up into the air to an even greater height. Although somewhat 

 slender, the stems and branches are exceedingly rigid and strong, owing 

 to the fact that the whole of the cortical tissue of the stem is strongly 

 selerenchymatous. When growing on the ground the characteristic foliage 

 of L. volubile is luxuriantly developed, such specimens being commonly 

 used for decorative purposes. When climbing, however, this foliage is 

 generally very poorly developed, and frequently is entirely wanting, the 

 branches being present simply as short peg-like projections scantily 

 clothed with the acicular scale leaves. The hooks are present on all 

 rapidly elongating stems and branches that are bare of the usual dorsi- 

 ventral foliage. The hook is formed by a short downward prolongation 

 of the base of the ordinary acicular scale leaf. They point backwards from 

 the elongating region of the stem, and, when the stem is scrambling or 

 twining, serve to take the weight of its lower parts. 



I have elsewhere (1-5, p. 366) described the characteristic heterophylly 

 of this species. Not infrequently in sheltered places throughout Westland 

 I have come across mature plants in which the dorsal and ventral scale 

 leaves, which are normally very reduced in size, are longer and more spread- 

 ing, the laterally spreading large leaves at the same time "tending to the 

 acicular form. This is of the nature of a reversion foliage, and such plants 

 have an exceedingly beautiful, feathery appearance. When the plants 



