Forest Vines to Snow Tussocks: The Story of New Zealand Plants
Vascular saprophytes are completely without chlorophyll and are often small, pale plants growing in leaf litter in very shady places in rain forests. It is thought that they gain their organic nutrients from decaying plant material. Their underground parts are penetrated by fungal threads and recent studies, some in New Zealand, have shown that in some cases the fungal threads are also attached to the roots of nearby trees. It has been suggested that such saprophytes, and probably others, may be secondary parasites drawing nutriment from tree roots via fungal threads.57,58
The New Zealand saprophytes are all orchids, except for one belonging to the Burmanniaceae, a family closely related to the Orchidaceae. This is Thismia rodwayi, 58 which has been found only in the northern half of the North Island, and there mostly on the volcanic plateau. The pinkish scale-leaved stems, arising from a branching root system, each end in a relatively large delicate flower, which has been likened to a red lantern. Our species is also found in Tasmania and Victoria and there are other species in Australia, tropical Asia and America.
Coryhas cryptanthus is the only saprophyte among the eight New Zealand species of the genus. It has been collected at scattered localities throughout the country. Only the flower appears above the leaf mould; the stem then elongates to carry the capsule to about 15 cm above the ground. The genus ranges from south-east Asia through Australia to New Zealand.page 97
The 15 species of Gastrodia ranging from India and Japan to Australasia are all saprophytes. The branching underground rhizomes are tuberous and filled with starch; those of the New Zealand species were eaten by the Maori. The stems are tall, up to 1 m, and can be attractively if strangely coloured. They often appear polished, with flecks of white and brown which give a resemblance to wood grain. G. cunninghamii and G. minor are found throughout, G. cunninghamii, mostly in beech forest, and G. minor mostly under Leptospermum. G. sesamoides has not been discovered further south than 42°S in the South Island and is found in open forest and shrubland.
Yoania australis was only discovered in recent times, but is now known from several localities in Beilschmiedia tarairi forest on the Northland peninsula. The stems bearing the small flowers are a pale rose colour and up to 20 cm tall. The genus is entirely saprophytic and is known at several localities in Asia and north Africa.