The Lycopods, or club mosses, are a small group of plants but they are important as a link between Pteridophytes and Gymnosperms. They were, at one time, a much more extensive group. In the Lycopodiaceae there are two distinct generations, as in ferns, but the prothallus, or gamete-bearing plant, is not an independent organism; it is colourless and lives underground, among the roots of other plants. The spores are found in strobili, or cones, at the tips of some branches. Little was known of the sexual generation of these plants before the work of a New Zealander, Rev. John E. Holloway, who found many of these underground prothalli, which he described in a series of papers published in The Transactions of the New Zealand Institute.
The two genera of Lycopodiaceae found in New Zealand are Lycopodium and Phylloglossum. Of the latter genus there is only one species, Phylloglossum drummondii, which is found also in Tasmania and parts of Australia. It is a very small unusual plant of about 5 cm, found mainly in North Auckland and in small areas in Marlborough and Banks Peninsula.
There are 12 species of Lycopodium, which is a larger number than that in other countries; also they are larger plants. The spore-bearing plant has wiry stems with closely appressed scale-like leaves, usually of very pale green colour. Some are epiphytes and others scramble over forest trees and shrubs, mainly on the margins of forests; they vary greatly in size, the smallest having short, erect stems. Lycopodium volubile (waewaekoukou, or owl's foot) is a graceful plant with branches 10–12 ft long. The stems are thin and wiry and bear two types of leaves. It scrambles over trees, manuka scrub, or just over the ground, and is common throughout both islands in lowland and montane areas. L. deuterodensum is a species common from North Cape to about 38° S; it has long-branched rhizomes from which arise rigid, erect branches bearing leaves of three kinds. In lowland and montane areas of the southern part of the North Island, L. scariosium is common in open country from 38° S. It has long wiry stems with tiny flattened leaves. L. fastigatum is a widespread species, of a variety of habitats, and of variable form. It is common in hilly country of the South Island. L. cernum has short, stout, much-branched stems bearing crowded, pale yellowish-green leaves. It is found from North Cape southward in lowland and montane bogs, but is specially abundant near the hot springs of the thermal regions.
There are two epiphytic species, L. billardieri and L. novae zealandicum. L. billardieri is common in lowland and montane forests; the hanging stems branch freely and are densely crowded with leaves. L. novae-zealandicum, of much more restricted distribution, is found mainly on tree ferns in parts of the North Island. The leaves are not so densely arranged on the drooping branches and are of very pale colour. Spores are on strobili at the ends of branches.
Of two plants closely related to the Lycopods, one is Tmesipteris, a small plant common in lowland forest, which is usually found as an epiphyte, but sometimes growing on rocks. The one species, T. tannensis, has dark-green leaf-like lobes with tiny sporangia at the tips. The other is Psilotum nudum, which is common in areas north and south of Auckland. Both are very unusual plants, survivals of a past age, with little relationship to plants of the present day.
by Olive Rita Croker, M.A., Botanist, Wellington.