PRECOCIOUS BLOOMING OF NEW ZEALAND PLANTS. 219 



a recent origin of the shrub-stage. Such, more probably, arose 

 gradually during a former dry period, when it may have gained, in 

 some cases, an independent existence, as shown by its sometimes 

 blooming, and its resemblance to the divaricating shrubs. At the 

 present time the mesophytic conditions favour the tree-form and 

 a reversion has taken place, while in course of time, if this view is 

 correct, the shrub-stage should be suppressed altogether; in fact 

 there are examples in the flora of early hardly or non-divaricating 

 shrubby stages of certain trees of this class. 



As for the divaricating shrubs themselves, nearly all are more 

 or less heteroblastic. Pittosporum divaricatum} (Pittosporacege) 

 and, to some extent, Corokia Cotoneaster (Cornacaceae) remain 

 juvenile in the shady forest, though just on its outskirts both are 

 intense xerophytes — i.e., both forms areepharmonic. Probably the 

 forest form blooms, but my notes have nothing on this head. Aris- 

 totelia fruticosa (Elaeocarpaceae), a shrub ecologically equivalent to 

 the last-named, has a most remarkable series of distinct leaf-forms 

 when juvenile, at which stage it not only flowers at times, but may 

 also occasionally remain fixed, as in an example noted by me near 

 the base of Mount Torlesse, Canterbury. In such a case the differ- 

 ence between the almost spiny small entire-leaved xerophytic adult 

 and the fixed juvenile form, with its much larger frequently pinna- 

 tifid leaves, is indeed striking. 



The whipcord Veronicas of the cupressoid growth-form pass 

 through a very distinct juvenile stage with hygrophytic leaves, 

 which is epharmonic, since, in the first place, the low stature of the 

 early seedhng and the shelter it receives from other plants, etc., 

 bring it rmder very much more humid conditions than those of the 

 adult ; and, in the second place, the juvenile form will persist for 

 a long period if cultivated in moist air and feeble light. Also, the 

 adult form is exceedingly plastic, and various stimuli will rapidly 

 bring about the formation of reversion-shoots. 



So far as fixed juvenile forms go amongst these cupressoid 

 Veronicas, Mr. T. F. Cheeseman made the important discovery of 

 a " variety " of Veronica tetragona growing in fair abundance on the 

 dry pumice and scoria of the subalpine volcanic plateau of the 

 North Island, of which plant he writes : " Probably it is an inter- 

 mediate state between the juvenile stage and the fully matured 

 one, but if so it must persist for many years. "^ 



A distinct species of Veronica, bearing the garden name of V. 

 cassinioides, reputed as having been first collected in S.W. Otago, 

 appears to me to be without doubt a permanent juvenile form, 

 intermediate between the early pinnatifid and adult scale-leaved 

 stages of the whipcord Veronicas, the adult of which is probably 

 extinct. A closely allied plant has recently been collected on the 

 Garvie Mountains by Mr. D. L. Popplewell, but not in flower, and 

 it may turn eventually into the cupressoid stage. 



1. This is in part P. rigidum Hook.f., but differs so much from the type that I am separating 



them. It is the shrub dealt with by me in Trans. N.Z. Inst. 33 ; pp. 264, 265, 266, 1901, and 

 my conclusions therein cited by Diels, loc. cit. p. 66-69. 



2. Trans. N.Z. Inst. 40 ; 281, 1908. (Italics mine.) 



