14 Transactions. 



great in numerous instances that the idea of " normal " loses its meaning* 

 Take the following examples : — 



(a.) Leptospermum scoparium Forst. (Myrtac.) may be a moderate-sized 

 tree, a tall shrub, a dwarf plant 2-8 cm. tall which flowers and ripens seed, 

 and an absolutely prostrate plant which forms a dense covering to the ground 

 and puts forth adventitious roots, although the erect forms are exceedingly 

 difficult to artificially strike as cuttings. 



(6.) Certain shrubs are of the xerophytic divaricating growth-form when 

 growing in the open, but of a comparatively loose, leafy, and mesophytic 

 habit when growing in the shade and shelter of the forest — e.g., Pittosporum, 

 divaricatum* Cockayne, Corokia Cotoneaster Raoul, Aristotelia fruticosa^ 

 Hook, f., &c. In such a case, were the shade form alone in existence (see 

 Plate VII, fig. 1), there is no botanist but would consider it fixed and 

 normal, and yet it is the sun and wind form rather that is so considered. 



(c.) Fuchsia Colensoi Hook. f. (Onagrac.) is a twiggy shrub in the open, 

 but in the forest it is frequently a scrambling liane. 



(d.) Hymenophyllum multifidum Sw. (Filic.) when occupying wet rocks 

 in the Auckland Islands has its fronds closely curled up, but when growing 

 in the forest interior of the same group they are quite flat. That the curled 

 fronds are not fixed I have shown by means of moist-air culture (1904, 

 pp. 266, 267). Suppose that H. multifidum was only found on a wind- 

 swept treeless island, such as Macquarie Island, no one would question 

 the curled frond being normal and fixed. 



(e.) Myoporum laetum Forst. f. (Myoporac.) is nearly always a small 

 round-headed coastal tree having a distinct erect trunk, but on Moko Hinou 

 Island it is altogether prostrate, and its branches far-spreading, cord-like, 

 and twiggy. Were it not that I have seen intermediate forms on some 

 parts of the North Island coast I could hardly believe that the Moko Hinou 

 plant was not a stable form. 



(/.) Myrtus pedunculata Hook. f. (Myrtac.) is generally either a small 

 tree or a twiggy erect shrub,% but at an altitude of some 1,200 m. in the 

 Nothofagus forest of the volcanic plateau, North Island, it is frequently 

 quite prostrate and rooting. StypheUa fasciculala Diels (Epacrid.), although 

 nearly always an erect shrub as a forest-plant, behaves exactly as the last- 

 named in the same station. On dunes it is also frequently prostrate. 



(g.) Dracophyllum politum Cockayne (Epacrid.) when growing on the 

 mountains of Stewart Island is a turf-making shrub, a low spreading shrub 

 with stout horizontal branches, or a massive ball-like cushion plant, accord- 

 ing to circumstances. So different are these various forms that I can 

 hardly yet believe them to be merely environmental unfixed forms of one 

 another§ and that my observation is not faulty. 



(h.) Gleichenia dicarpa R. Br. and G. circinata Sw. (Filic.) differ speci- 

 fically in the former having the margins of the segments of the pinnae in- 

 curved so as to be pouch-shaped, whereas those of the latter are virtually 

 flat. But the same individual of the var. hecistophylla Hook. f. will possess 



* This plant has been merged with P. rigidum Hook. f. A diagnosis has not yet 

 been published, owing to lack of sufficient material, but it is necessary here to use a 

 definite name, since P. rigidum and P. divaricatum are certainly distinct entities. (See 

 Plate I.) 



t For further details, see Cockayne, 1901, pp. 265-67, and Diels, 1906, pp. 66-69. 



% It is possible that the tree and shrub are different species, but I hardly think 

 so, though I have not seen intermediates. 



§ See Cockayne, 1909, p. 16, and photo No. 13, facing p. 17. 



