Some of the most striking plants on rocky mountains are the vegetable sheep, or species of Raoulia, belonging to the Compositae family. The apt name, vegetable sheep, is principally applied to R. mammillaris and R. eximia, which as densely compacted, rounded cushion plants grow to several feet across and sometimes 2 ft high. R. eximia occurs in the Southern Alps from about mid-Canterbury southwards and the white colour of its flowers and also of the hairy covered leaves gives it the appearance, from a distance, of sheep. The cushions are formed by a multiplicity of branches, the ends of each branch being covered with the small woolly leaves. The stems and leaves are packed into a dense, hard, rounded mass. The inside of the cushion rots to form a spongy peat and into this the living branchlets send roots. Other species forming similar types of cushions are R. rubra of the Tararua Mountains, of much lesser size than R. eximia; R. goyenii on Stewart Island, greenish in colour instead of white; and R. buchananii of Fiordland.
Some species of Raoulia form mats, the commonest being R. australis. Its silver and green mats were to be seen everywhere in the dry parts of the South Island during the period when rabbits severely depleted the vegetation. Raoulia increased greatly at the expense of other vegetation. Since rabbits have been almost eliminated from this country, the plant is being gradually replaced. R. australis occurs from about the centre of the North Island southwards, and R. tenuicaulis is found even further north – from about Thames.
Altogether, there are about 20 species in New Zealand, all of them endemic. A few others have been described from New Guinea. The limits of some of the New Zealand species are hard to determine because of their variability and possible hybridisation.
The name vegetable sheep is applied also to species of genus Haastia, plants with similar characteristics and also endemic to New Zealand.
by Alec Lindsay Poole, M.SC., B.FOR.SC., F.R.S.N.Z., Director-General of Forests, Wellington.