310 



PLANTS OF NEW ZEALAND 



by the underlying green, and sometimes blotched with green 

 or brown near the teeth. In this stage the stem is usually 

 simple, and readies a height of from fifteen to twenty feet. 

 (./.J After a long period of growth, these simple hnear leaves 

 are followed by dark-green compound leaves, consisting of 

 three to five leaflets, 8-10 in. long, with petioles several inches 

 m length. These leaflets are not so thick and rigid as those of 

 stage (e) , and the stalks are not yet more than half-an-inch in 

 length, (g) The succeeding leaves are of a similar type, but 

 have longer petioles, and the leaflets are broader and thicker. 

 If the stem is branched, the plant now occasionally flowers. 

 (h) This is the final stage. The leaves again become simple, 

 but are, at first, not otherwise difl'erent from the previous 

 stage. The following leaves, however, become very hard and 

 thick, the teeth gradually become fewer and more distant, and 

 sometimes disappear altogether. The leaf of the mature 

 plant is from 4 in. to (j in. in length, linear, almost or quite 

 entire, hard and thick, dark green with prominent midrib, 

 jointed to a short, thick petiole. Probably such an extra- 

 ordinary series of changes in the leaf-form of any tree is 

 unique. It must not be supposed that all the species go 

 through as many transformations as P. crassifolium, though 

 all of them show many variations in leaf shape. In P. crassi- 

 folium., var. unifoliolatum, the deflexed leaf-form passes by 

 imperceptible gradations into the final stage, and there is no- 

 trifoliate stage. The later deflexed leaves become, in this case, 

 very coarsely toothed, incised, and expanded at the tips, before 

 adopting their final form. If the head of the tree is destroyed, 

 shoots are developed at the base, and these again reproduce 

 the long, black, toothed leaves of the juvenile form ; but the 

 leaves in this case are frequently not deflexed, but horizontal. 

 Kirk's statement that the large toothed simple leaves pass, as 

 a rule, more gradually into the mature state in the South 

 Island than in the Noi'tli, (Forest Flora, p. 60), scarcely seems 



