Climbing ferns are a feature of our forest, and there are also many perching ferns. Some of these have been mentioned already as mange mange, Lygodium articulatum, which climbs by its midribs, the perching Asplenium flaccidum, and others. The Polypodiaceae is a large family of ferns, mainly of climbing or creeping habit. The fronds are usually simple, firm or leathery in texture, with prominent sori and covered on the under surface by light-coloured hairs. Five genera are represented in New Zealand, the names of which have undergone various changes, as shown in brackets. The genus Pyrossia is represented by P. serpens (Cyclophorus serpens), with a large rhizome thickly covered with brown scales it climbs up trunks of trees or over rocks. This small fern is found everywhere, the very thick leathery entire leaves vary in shape, and have a thick felting of star-shaped hairs. There are three species of the genus Microsorum (Phymatodes or Polypodium), M. scandens, with long, much branched rhizomes, covered with dark-brown scales, and M. diversifolia, with irregularly lobed, bright-green fronds. Both are very abundant on trees and rocks. M. novae zealandiae is a larger fern with stout rhizomes and large leaves, deeply cut; it is confined to forests in the North Island. There are four species of the genus Grammatis (Polypodium) which are small perching ferns. Anarthropteris lanceolata (Polypodium) represents another genus; it has simple, bright green, rather fleshy leaves, and is common on tree trunks, especially in the north. Ctenopteris heterophylla (syn. Polypodium grammatidis and Grammatis heterophylla) is abundant throughout the country as an epiphyte.
Our ferns provide much of interest. A number hybridise vigorously; some have variant forms not fully understood, and probably with further research the number of our species will be increased. In the meantime many problems await the keen investigator. A rich field is open also to the horticulturist, since many of our species are easy to grow. From various points of view, then, New Zealand can count itself fortunate in its rich bounty of ferns.
Note: The names used in this article differ in some cases from those in Allan's Flora. As regards the Hymenophyllaceae, Mecodium, Sphaerocionium, Craspedophyllum, and Apteropteris are listed in Allan as subgenera of Hymenophyllum and Macroglena; and Selenodesmium and Cardiomanes as sub-genera of Trichomanes. Allan's names are listed in brackets in the following list of generic names: Leptopteris (Todea), Dicranopteris (Gleichenia), Cyclosorus (Thelypteris), Microsorium (Phymatodes), Lastreopsis hispida (Rumohra hispida).
by Marguerite Winifred Crookes, M.A., Botanist, Auckland.
- New Zealand Ferns, Crookes, M. W., and Dobbie, H. B. (1963)
- Flora of New Zealand, Vol. 1, Allan, H. H. (1961)
- The Vegetation of New Zealand, Cockayne, L. (1928)
- Manual of New Zealand Flora, Cheeseman, T. F. (1925).