Significance of Spines in Discaria Toumatou. 83 
escence frequently eaten 1 by sheep, although protected by very 
spinous bracts. It seems much more correct to consider the spines 
of Discaria and the pungent yucca-like leaves of the Aciphylla in 
question as xerophytic rather than protective “ adaptations,” 
especially when their minute structure, 2 which need not here be 
detailed, is considered. 
Certain other peculiarities in the New Zealand flora support 
this view. Take for instance the case of the “ whipcord Veronicas.” 
These are curious shrubs which in their form “ mimic ” certain 
species of Cnpressus, one indeed being named by Hooker, Veronica 
cupressoides. All have scale-Jike, much reduced leaves, which are 
pressed very closely against the shoot-axis. They grow in those 
stations of the montane, subalpine and alpine regions, where 
transpiration is frequently excessive and changes of weather 
abrupt; some being found on those most extensive screes, termed 
in New Zealand “ shingle-slips,” which, as Schimper has stated, 3 
are true alpine deserts. Others occur on dry rock-faces, 
river-terraces, stony slopes and the like. All these Veronicas, so 
far as they have been investigated, are in their early seedling form 
typical hygrophytes, having numerous fully developed leaves. 4 Also 
as Goebel showed some time ago, 5 the adult speedily reverts to the 
juvenile form on cultivation in moist air. Subsequently I placed 
certain seedling whipcord Veronicas in a moist chamber and 
thus cultivated them for a number of years. Plants of Veronica 
Armstrongii, T. Kirk 6 grown in this manner for six years, and 
Veronica tetrasticha, Hook f. for more than four years, did not 
assume the cupressoid habit, although both reached a considerable 
size, the latter plant indeed almost attaining its full adult height. 
Pittosporum rigidum, Hook, f., when growing normally in the open, 
is a shrub of most dense habit, well deserving its name; but a plant 
1 In winter hares feed upon the thick root, and for this reason 
amongst others, the thickets of this remarkable plant are 
less abundant than formerly. 
2 For Anatomy of leaf, stem and spine of Discaria see A.C. 
Finlayson on “ Stem-structure of some Leafless Plants of 
New Zealand.” Trans. N. Z. Inst. Vol XXXV., 1903. pp. 361- 
62 ; and for leaf-anatomy of Aciphylla Colensoi, see L. Diels, 
“ Vegetations-Biologie von Neuseeland.” Engler’s Bot. 
Jahrb. Vol. XXII., 1896., p. 267. and Fig. 5 a., p. 268. 
3 Pflanzengeographie, p. 797. 
4 Cockayne. Trans. N.Z. Inst., Vol. XXXI., p. 378, and Vol. 
XXXIII, p. 289. 
5 Pflanzenbiologische Schilderungen, Tcil I., p. 19. 
6 See Fig. of juvenile plant and adult shoot. Trans. N.Z. Inst., 
Vol. XXXI , plates 28, 29. 
