488 PROCEEDINGS OF SECTION D. 



Director of tlie Singapore Botanical Gardens ; to Dr. M. Treub, of 

 Buitenzorg ; and to the Forestry Department of the Philippines. 

 Without going into details, it seems clear that the Asiatic and Australian 

 species exhibit no heterophylly such as the genus does in New Zealand, 

 while as to the New Caledonian species nothing has been said of their 

 leaf variation ; but, as Diels writes to me, the specimens of these at 

 Berlin " are not large enough for a definite opinion to be expressed." 

 If this is a fact that the extra-New Zealand species show no marked 

 heterophylly, then there seems, so far as New Zealand is concerned, 

 to be a crucial case in Parsonsia, for in one small region there is a genus 

 behaving, so far as its life history is concerned, differently altogether 

 to what it does in the rest of its area of distribution. And this, taken 

 in conjunction with the fact that about 200 species of New Zealand 

 plants, i.e., some 12 per cent, of the spermophytes, belonging to most 

 diverse genera and natural orders, exhibit heterophylly of a more or 

 less striking character in their life-histories, seems to distinctly point 

 to there being some reason in New Zealand itself for this special phe- 

 nomenon ; and this reason, it seems to me, must be sought for in the 

 manifold changes which the geological history of the New Zealand 

 archipelago has brought about. This explanation (1) was first given 

 by Dr. L. Diels regarding the occurrence of extreme xerophytic structure 

 in New Zealand, and since that time evidence in other directions has 

 come forward to support his bold and splendidly conceived theory. (2) 



As for the special case of the Parsonsia species, it seems possible 

 that the various leaf forms are epharmonic adaptations evoked by 

 ancient environments, and that the species, like those alluded to above, 

 are not fixed as yet, but remain eminently " plastic." Nothing can 

 be clearer, too, than that lianes, all the world over, are ligneous or 

 herbaceous plants, which have gradually adopted the chmbing habit 

 through forest conditions. In the case of Parsonsia, too, the primary 

 small orbicular leaves put one in mind of those small-leaved shrubs 

 {Coprosma species, &c.), so common in xerophytic stations in New 

 Zealand at the present time. 



Also, there are several examples amongst New Zealand plants 

 where the same genus furnishes both shrubs, lianes, and even herbs. 

 Thus the genus Senecio is made up of shrubs, one low forest tree, various 

 herbs, and the climbing S. scio'dophilus. There is the herbaceous 

 Angelica gingidiun and the climbing A. geniculata. But more striking 

 are the fuchsias, where there is the forest tree. Fuchsia excorticata, 

 and the closely-alUed F. Colensoi, which is a shrub pure and simple in 

 the open, but in the forest occasionally a scrambling hane. Finally 

 the third species of Fuchsia, F. procumbens, is a coastal liane of Northern 

 New Zealand, chmbing near the upper strand over tall sedges and the 

 like. 



The long narrow leaves would be explained in a similar manner, 

 they being tlie early climbing leaves after the liane habit had been 



(1) Vegetations- Biologic. — von Neuseeland, Eng., Bot., Jahob., xxn., B. 2 Heft., 



1896, pp. 246-247. 



(2) Cockayne, L.— Various papers in Trans. N.Z., Inst., especially from vol. xxxiil., 



1901, to vol. xxxix., 1907. 



