268 MR. R. S. ADAMSON ON THE COMPARATIVE ANATOMY 
conditions and are not now very plastie, as is seen from the very slight 
structural differences between native-grown and cultivated plants of the 
same species. 
Distribution of Veronica *. 
Of all the species of Veronica found in New Zealand, only about three 
occur elsewhere. The others are all endemic fT. Of these also more than 
two-thirds are confined to the South Island and to the eastern side of it T. Of 
the species examined, those that occur in other parts are either the less 
xerophilous species, V. salicifolia, Г. Cookiana, or montane species, which in 
the North Island grow near the summit of mountainsf especially in the 
Hawkes Вау District. 
Veronicas do not occur in the forest-regions of the west, with the exception 
of the coastal species *, but are abundant in the *elfin-wood " and upper 
regions of the east. 
Correlated with these conditions is the more or less xerophilous structure 
of all the species examined—a feature common to many plants of the east 
side of the South Island +. Most of the species with spreading leaves come 
under Hansgirg's Myrtus type of leaf, and the others in his /riea type $. 
The xerophily is arrived at in various ways : the most obvious being those 
features mentioned above—reduction of leaf-surface, of the intercellular 
space system, and the cuticularization of the epidermis. Some special 
features may be mentioned :— 
Stomata.—Stomata vary greatly in size and distribution through the different 
species. In most cases they occur irregularly scattered over both sides of the 
leaf ; sometimes they are absent from the upper side, but none of the species 
showed a complete absence from the under side. In number there is great 
variation : in Group A stomata are numerous below and scarce above— 
e. g., V. Cookiana has about 2200 per sq. mm. below and only a tenth of 
that number above ; in the more xerophilous forms the numbers (about 
250—400 per sq. mm.) are approximately evenly distributed on the two sides. 
In six species stomata are absent from the upper side : V. Hectori, V. cupres- 
soides, and V. propinqua have the upper surfaces closely pressed against the 
stem ; and of the others, V. Z/ulkeana and V. elliptica have опе or more 
layers of hypoderm along the upper side. 
A noticeable feature, especially in the more xerophilous forms, is the 
presence of curved expansions of cuticularized wall over the stomatal 
|. In the simplest cases these take the form of a slight thickening 
aperture 
over the guard-cells ; more often, however, the wall in this region projects 
* Engler (1882). + Cheeseman (1906) 
t Herriott (1905). § Hansgirg (1903). 
| Diels (1897). 
