The cosmopolitan carrot family or Umbelliferae is well represented in New Zealand. The largest genus is the peculiar and distinctive spear-grass one. It contains nearly 40 species, all of which are confined to this country. Only two others occur in the genus and both are found in the Australian Alps. The native ones are found in tussock grassland and are particularly characteristic of alpine vegetation. There are early records from explorers of almost impenetrable thickets of spear grasses and Irishman, but these were destroyed by fire to make way for sheep. Sheep, together with rabbits, keep the plants down, but these quickly reappear once the animals are taken off the country.
Leaves are swordlike and tipped by spines, while the long flowering stalks carry spiny bracts. The species are difficult to identify. Some of them are connected by intermediate forms, while hybrids are certain to occur. A. colensoi, taramea, is found in montane and subalpine vegetation in both islands. It has stout stems up to 3 ft tall, with leaves 1 to 2 ft long and about half an inch or more wide. The whole plant resembles a mass of bayonet-like spines. The flowers are small, greenish-yellow and are arranged in small umbels along a stout, erect stem which can be 6 ft or more long. A. squarrosa is a much smaller plant, and the Maoris obtained a prized scent from its resinous gum.
Some of the species, especially the alpine ones, are quite small and some have very limited distributions. Thus A. polita of the Tararua Range and northern mountains of the South Island is often under 6 in. tall. The leaves are divided two to three times. A. monroi is a small tufted plant in the mountains of the upper half of the South Island. The leaves are pinnate.
by Alec Lindsay Poole, M.SC., B.FOR.SC., F.R.S.N.Z., Director-General of Forests, Wellington.