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Forest Vines to Snow Tussocks: The Story of New Zealand Plants

Pendent Epiphytes

Pendent Epiphytes

Four New Zealand wide pteridophyte species often grow as epiphytes with their roots or rhizomes embedded in the soil of epiphyte nests. Though they occur elsewhere as well it is in these sites that their growth is most vigorous and their pendulous stems or leaves attain their maximum length. Of the four, Lycopodium varium is the most impressive; its slender stems sometimes forming huge masses up to 1.5 m long, below asteliad nests (Fig. 42). The stems branch repeatedly by equal forkings or dichotomies, so that they form a dense but well balanced mass. It is almost constantly in motion as even the lightest breeze can set the tassels swaying. In their upper parts the stems are clothed by small spreading leaves, which grade into small, close-set scales enclosing the sporangia towards the branch tips. Lycopodium varium is restricted to New Zealand, but there are related species in tropical forests.

The ferns Asplenium polyodon (= A. falcatum) and A. flaccidum may have leaves of a metre or more in length below the epiphyte nests. A. polyodon, with its double-toothed, wedge-shaped leaflets is perhaps the most attractive of the New Zealand species of the genus (Fig. 40). A. flaccidum has an unusual stringlike appearance with long and narrow, deeply-toothed leaflets (Fig. 43). Dobbie aptly describes the leaves of this species as appearing to have been 'cut from a piece of pale-green leather'. Asplenium polyodon is found from India to Australia and the Pacific and A. flaccidum in Australia and some Pacific Islands. Both Aspleniums and Lycopodium varium extend into montane cloud forests, but there they depend from mossy trunks and branches.

Tmesipteris, a genus restricted to the south west Pacific, is sometimes referred to as a 'living fossil' as it is considered to be one of the most primitive genera of land plants. One of the highlights for botanical visitors to New Zealand is to see a living plant of this genus. Tmesipteris elongata subspecies robusta has been observed growing from Collospermum clumps at a number of localities through the North Island, but not yet page 75
Figure 42 (opposite left) Hanging tassels of Lycopodium varium below an asteliad nest.Photo: M. D. King.

Figure 42 (opposite left) Hanging tassels of Lycopodium varium below an asteliad nest.
Photo: M. D. King.

Figure 41 (opposite above right) Close view of a Collospermum hastatum leaf fan showing the dark leaf bases and roots between the decaying outer leaves. The arrow indicates where water is seeping from the reservoirs between the leaves. Photo: J. W. Dawson.

Figure 41 (opposite above right) Close view of a Collospermum hastatum leaf fan showing the dark leaf bases and roots between the decaying outer leaves. The arrow indicates where water is seeping from the reservoirs between the leaves. Photo: J. W. Dawson.

Figure 43 (opposite below right) Epiphytic plant of the fern Asplenium jlaccidum.Photo: M. D. King.

Figure 43 (opposite below right) Epiphytic plant of the fern Asplenium jlaccidum.
Photo: M. D. King.

page 76in the South Island. Its stems, with their small, simple leaves, are unusually long for a Tmesipteris and dichotomise freely. Other species of Tmesipteris rarely branch.

Three orchid species can also be included as pendent epiphytes. The two Earinas belong to a small genus with other species in New Caledonia and Polynesia, but this genus is considered to be closely related to the larger Epidendrum of tropical America. Both species have spreading rhizomes and can sometimes extend for several metres along branches. The stems bearing the leaves droop downwards and can be 30 cm or more long. The leaves are formed in two rows, more or less in one plane; those of E. mucronata are narrow, thin and quite grasslike while those of E. autumnalis are broader and thicker, in keeping with the more robust nature of the plant as a whole. Both species form terminal sprays of small flowers, E. mucronata in the spring and E. autumnalis in the autumn. The flower clusters of E. mucronata hang down and are yellowish orange, those of E. autumnalis turn upwards and are waxy white with a strong spicy perfume.

Our sole species of the large tropical genus Dendrobium (D. cunningh-amii) is the largest of New Zealand's epiphytic orchids. Its freely branching stems and narrow leaves form feathery drooping masses. The stems are polished, often bright yellow and very bamboo-like in appearance. The white, reddish-centred flowers are scattered and while modest by tropical standards are, at 2-2.5 cm in diameter, the largest among our epiphytic orchids.