(Olearia and Senecio spp.).
In the family Compositae (which are mostly herbaceous), shrubs and trees are sometimes a feature of high altitudes in the tropics. In temperate New Zealand, however, the two composite genera, Olearia and Senecio, contain a large number of woody species, some of which are commonly called tree daisies. Olearia has only woody species, but in Senecio the plants range from herbs to small trees. They occur most commonly and extensively in alpine shrublands but species do occur in most types of vegetation. Life forms vary from dwarf shrubs to small trees, and more than one species is epiphytic and one is a liane. All the 40 or more species of Olearia found in New Zealand are endemic. About twice that number are found in Australia and Tasmania. Senecio is one of the largest plant genera, containing over 1,500 species, and is cosmopolitan. Over 20 woody species occur in this country and all are endemic.
S. kirkii is one of the most beautiful plants in the flora. It occurs as a ground plant or an epiphyte in forests of the North Island, particularly in North Auckland. The 2–in.-wide daisy flowers occur in large inflorescences which are sometimes so plentiful that the leaves are almost hidden. S. greyii is a small, hairy shrub with a natural distribution confined to the cliffs of the Wellington east coast, but is very common as a garden plant. S. sciadophilus is a slender shrub often reaching 15 ft in height. The most widely distributed woody Senecio is S. elaeagnifolius. It occurs in mountain shrubland, sometimes extensively, throughout the country.
Amongst the Olearias are several species occurring commonly in lowland shrubland. O. furfuracea, or akapiro, is one of the commonest of these in the North Island. It is found in shrubland along stream banks and forest margins. O. rani, or heketara, is a shrub or small tree reaching 25 ft found throughout lowland forest in the North Island and the northern tip of the South Island. The flowers, in very large panicles, make the tree conspicuous during the months of October and November. Several species have small linear or almost linear leaves. Some of these are not well known and need investigating, particularly those varieties related to O. virgata. This species itself occurs throughout New Zealand in lowland shrubland and boggy ground, from about latitude 37°. One or two of these small-leaved species have sweet-scented flowers.
O. angustifolia is a very attractive plant with purple flowers and comes from coastal areas along Foveaux Strait.
by Alec Lindsay Poole, M.SC., B.FOR.SC., F.R.S.N.Z., Director-General of Forests, Wellington.