plant growth is characteristic of semi-desert regions, where the points of similarity of environment to those of the mountain-tops are evident. This cushion form has many advantages for the alpine plant. It keeps it warm in winter and cool and damp in summer; it allows it to produce a great amount of blossom without the necessity for extensive growth; it resists the utmost efforts of furious gusts of wind almost as well as would a half-buried stone; on the most storm-swept cliffs its fresh green blobs “welcome every changing hour, and weather every sky.” Fig. 32 shows a boss of this kind, composed of the Cushion Pink (_Silene acaulis_), with an admixture of Filmy Fern (_Hymenophyllum unilaterale_) and a Moss (_Mnium hornum_). The shrubs of the alpine zone are mostly small and creeping, weaving themselves among the vegetation, and with low grasses and sedges forming a mat which is equally resistant to all inimical conditions. Their leaves are small, to avoid damage by wind or by excessive transpiration. In some genera--for instance, _Veronica_--the diminution of leaf surface accompanying more elevated habitat is very striking. In the New Zealand lowlands broad-leaved forms (Fig. 34, _left_) are met with, which give way, as one ascends to 8,000 feet, to such forms as _V. Hectori_ (Fig. 34, _right_), in which the leaves are reduced to mere scales, and the plant much resembles some of the Cypresses or other Conifers with marked xerophile characters. Other plants, again, escape climatic rigours by burrowing underground and throwing up short aerial stems in summer; the spindly plants of the lowland, with diffuse stems, and also the light-rooted annuals, [Illustration: FIG. 34.--NEW ZEALAND SHRUBBY VERONICAS, SHOWING, FROM LEFT TO RIGHT, REDUCTION OF LEAF WITH INCREASING ELEVATION OF HABITAT. 2/3.]