Cockayne. — Development of Seedlings. 293 



The first seedling leaf-form much resembles the early seed- 

 hug leaf of Bubus australis, var. glaber, whereas the second 

 form is like the reduced lamina of an adult leaf (cf. figs. 40 

 and 44). 



The difference in appearance between B. cissoides when a 

 liane of the forest and when it forms a round mass of inter- 

 twining branches and midribs in the open is quite as strik- 

 ing as that of Pittosporum rigidum, described earlier in this 

 paper ; but there is this great difference : that the forest form 

 of Pittosporum rigidum is the early seedling form still main- 

 tained, whereas the forest form of the Bubits in question 

 more resembles the second seedling stage of the latter. 

 In both, however, the form in the open is a direct adapta- 

 tion to xerophytic conditions, though whether this form is 

 hereditary in our plant I am not in a position to determine. 

 This in large measure arises from the fact that, so far as I 

 know, the extreme xerophilous form has never been observed in 

 flower or in fruit. In order to verify my own observations I 

 wrote to Messrs. T. F. Cheeseman and D. Petrie,* inquiring if 

 they had ever seen this particular form of the plant in fruit, 

 &c, and both these botanists, of most wide experience with 

 regard to New Zealand plants, replied that they had never seen 

 the almost leafless form in flower or fruit. Mr. Cheeseman 

 qualified his information with the remark that he saw no reason 

 why it should not flower. That is indeed very true, since poor 

 soil, as every observant gardener knows, causes early flower- 

 ing, while, on the other hand, it is a proved physiological 

 fact that a moist atmosphere will hinder the development of 

 the reproductive organs in plants.! Here, then, is quite a 

 case to the contrary : the plant of the moist wood produces 

 fruit regularly, the plant of the barren wind-swept slope 

 rarely or never does so. 



The forest liane climbs over tall shrubs or low-growing: 

 trees. It is well furnished with leaves, which are pinnately 

 trifoliate, with the leaflets equal in size, or the terminal one 

 is often the largest. The margin varies from coarsely and 

 deeply toothed (fig. 42) to merely waved. The leaf-surface 

 is usually bright-green and shiny, and always quite glabrous. 

 The leaflets are from broad to narrow lanceolate in shape, 

 rounded at the base, and articulated to the usually rather long 

 channelled petiolule, that of the terminal leaflet being much 

 the longer. Petioles, petiolules, and midribs may be quite 

 unarmed in the most extreme cases, or furnished with few 

 or many pale-coloured prickles. Such leaves may measure 



* Mr. S. D. Barker also informs me he has never seen flowers, &c, 

 on this plant. 



t Sohimper, A. F. W., " Pflanzen-Geographie," Jena, 1898, pp. 30, 31. 



