PROCEEDINGS OF SECTION D. 487 



secondary long and narrow one. Between these two there are all 

 kinds of intermediates (see figs. 1, 2, 15, 11, 21), and, moreover, "re- 

 version shoots " freely occur, thus bringing primary leaves quite out 

 of their proper place in the sequence. 



The leaves which succeed the cotyledons are certainly variable 

 in size and shape, but they are always of what may be called the short, 

 broad type (see figs. 13, 14, 19, 20). Sometimes they are quite small 

 and almost circular, at other times various varieties of oblong pre- 

 dominate. The next phase of development is an increase in length 

 and narrowing of the base of the lamina (see figs. 5 and 6), so that in 

 the most extreme cases a well-marked spathulate leaf is the result 

 (see figs. 21 and 11). Then the circular leaf apex of this latter is lost, 

 and the second leaf form, a long and narrow leaf, comes into being 

 (see figs. 3, 4, and 24). This second stage persists for some consider- 

 able time, i.e., there is a prolonged juvenile form; but sooner or later, 

 when, by the twining of the ever lengthening stem round its support, 

 the brighter light is gained, the adult and third form appears, the leaves 

 large and broad and of a more or less oblong character (see fig. 25). 

 These adult leaves vary a good deal in different individuals and in 

 various localities, but they are of one type and are quite distinct from 

 those of the two juvenile stages. 



Parsonsia capsularis, to which all the remaining forms of Parsonsia 

 in New Zealand have been hitherto referred, commences its development 

 in exactly the same manner as P. heterophjlla, so that in their early stages 

 the two species are quite indistinguishable. There is the early circular 

 leaf, the narrowing of the base of the lamina, the spathulate leaves, 

 and the long, narrow leaf ; but at this stage, in one very distinct form 

 of P. capsularis, further development always stops, and the adult leaf 

 in this case is identical with that of the second stage of P. heteropyllah, 

 i.e., the adult of the one species is merely a -fixed juvenile form of the other. 

 But this is not so for all forms of P. capsularis, since the adult of some 

 proceed further and resemble rather narrow-leaved adult forms of 

 P. heterophylla. This matter, too, is complicated by the fact that it 

 is almost certain that natural hybrids between the two species are not 

 uncommon. All the same, one particular form, unnamed as yet, 

 which occurs chiefly as a liane in dry mountain stations of the south 

 island of New Zealand, never assumes a special adult form, but is 

 merely, so far as its leaves go, a fixed juvenile form of P. heterophylla. 

 This also opens up the question of specific rank, and it seems to me 

 abundantly clear that any plant, such as this, ivith a peculiar life history 

 of its oivn, must he considered a distinct species. 



So much for the New Zealand species. Now comes the question, 

 how do the species of Parsonsia without New Zealand behave as to 

 leaf-changes ? Evidently, from their distribution, the species should 

 be closely related and should be descended from some common ancestor. 

 In order to throw some light on this most important matter I applied 

 for information and specimens to my esteemed correspondent, Mr. 

 H. J. Maiden, Director of the Sydney Botanic Garden ; to Mr. R. T. 

 Baker, of the Sydney Technological Museum ; to my friend Dr. L. 

 Diels, of the Royal Botanical Museum of Berlin ; to Mr. H. N. Ridley, 



