Forest Vines to Snow Tussocks: The Story of New Zealand Plants
At higher altitudes in sheltered hollows, such as cirques or smaller depressions, snow will persist well into the growing season. Plants growing in such sites must be able to reproduce in just a few months, but they have certain advantages over the plants of the surrounding fellfield. They have more shelter from gales and, with reduced erosion on their concave slopes, a deeper soil which has a steady if cold supply of water from the gradually melting snow. The flowers of some of the snow bank plants may actually open beneath the melting snow. This is the case for two species of Caltha with their Ranunculus-like flowers, those of C. obtusa being white and C. novae-zelandiae yellow. Snowbank plants form a continuous sward, with the snow patch grass, Chionochloa oreophila, usually page 192predominating. Among other prominent plants are Ranunculus sericophyllus with deeply divided leaves and relatively large yellow flowers; Celmisia allanii, with patch forming rosettes of fluffy pale grey to snow white leaves; the related but pale green C. haastii, and two mat forming species, which although flowering plants look remarkably like mosses — Raoulia subulata and Drapetes lyallii.