Drymoanthus minutus

Projecting small unbranched fan-like epiphytes with relatively thick roots and a short thin fibrous leafy stem, the relatively small, narrow crowded leaves arranged in 2 ranks. Inflorescences are short, sturdy and unbranched. The small uncrowded fragrant flowers are green with a white labellum. They have relatively narrow projecting or incurved segments and a stiffly attached projecting labellum which lacks a spur and a prominent callus. The column is short without a column foot.

Significant Generic Characters

Epiphytic orchids; plants small, unbranched; stems short, thin, fibrous; leaves small, thinly coriaceous, crowded, in 2 ranks, longer than wide; racemes short, relatively thick; flowers small, lasting few to several days, fragrant; perianth segments moderately thick-textured; sepals subsimilar; petals subsimilar to the sepals; labellum firmly attached to the column base; lamina unlobed, without a spur; callus obscure; column short, without a foot; pollinia 4, sessile on a stipe, in 2 unequal pairs.

Size and Distribution

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A small genus of 4 species occurring in New Caledonia, New Zealand and Australia where there is a single endemic species, Drymoanthus minutus, between Cairns (2613 S)  and Townsville (1916 S) in northeastern Queensland. State occurrence: Queensland.

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Ecology

Drymoanthus minutus grows on shrubs and trees in rainforest, streamside vegetation and in swampy areas at low to moderately high altitudes.

Biology

Pollination: The flowers of Drymoanthus minutus last a few days and are probably self-pollinating.

Reproduction: Reproduction in Drymoanthus minutus is solely from seed. Seed dispersal takes 10-12 months after pollination and the capsules develop in a porrect position. Apomixis is unknown in the genus.

Seasonal Growth: Plants of Drymoanthus minutus grow mainly during the spring and summer months and are relatively quiescent for the remainder of the year.

Flowering: Drymoanthus minutus flowers in summer.

Hybrids: Natural hybrids involving Drymoanthus minutus are unknown.

Derivation

Drymoanthus, which is derived from the Greek drymos, forest and anthos, flower, refers to the habitat of the species.

Botanical Description

Perennial, evergreen, epiphytic herbs, monopodial. Roots relatively thick, elongate, straight or convolute, adherent. Plants small, porrect. Stem short, fibrous, rarely branched. Pseudobulbs absent. Trichomes absent. Leaves few, lasting several seasons, distichous, sessile, longer than wide, flat, thinly coriaceous, smooth; base sheathing the stem, persistent after leaf abscission, imbricate; margins entire. Inflorescence lateral, racemose, porrect to pendulous, multiflowered. Peduncle shorter than the rhachis, with few imbricate scarious bracts.  Rhachis straight. Floral bracts scarious, sheathing the base of the pedicel. Pedicel short, obscure, merging with the ovary. Ovary short, straight. Flowers resupinate, small, stalked, opening sequentially, lasting few to several days, brownish (non-Australian) or greenish, fragrant. Perianth segments moderately thin-textured, incurved or spreading. Dorsal sepal free, subsimilar to the lateral sepalsLateral sepals free, subsimilar to the dorsal sepal, flanking the labellum. Petals free, subsimilar to the sepals or slightly shorter. Labellum stiffly attached to the base of the column, markedly dissimilar in size and shape to the sepals and petals, ecalcarate. Labellum lamina apparently unlobed, cymbiform, porrect, margins entire, erect. Spur absent. Callus obscure, sometimes an unadorned grooved plate. Nectar absent (?). Column short, porrect from the apex of the ovary, lacking free filament and style, fleshy, nearly straight. Column wings obscure, small, tooth-like. Column foot absent. Pseudospur absent. Anther terminal, incumbent, 2-celled, persistent, smooth, with a short straight rostrum. Pollinarium present. Pollinia 4 in 2 appressed pairs, unequal, orange, hard, waxy, sessile. Stipe well-developed, long, narrow. Viscidium present, small, at an angle to the stipe Rostellum ventral, elongate, bifid. Stigma large, entire, concave. Capsules dehiscent, glabrous, porrect; peduncle not elongated in fruit; pedicel not elongated in fruit. Seeds numerous, light coloured, winged.

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Taxonomy

Within the Vandeae, Drymoanthus is characterised by small unbranched plants, unlobed labellum lacking a spur and column without a column foot and, 4 sessile pollinia  in 2 unequal pairs.

Notes

Drymoanthus minutus plants can flower when still very small.

Nomenclature

Drymoanthus Nicholls, Victorian Naturalist 59: 173-175, fig. (1943). Type species: Drymoanthus minutus Nicholls.

Infrageneric Taxa: No infrageneric taxa are currently recognised.

References

Dockrill, A.W. (1967). Australasian Sarcanthinae. The Australasian Native Orchid Society, Sydney.

Dockrill, A.W. (1969). Australian Indigenous Orchids. Volume 1. The Society for Growing Australian Plants, Halstead Press, Sydney.

Dockrill, A.W. (1992). Australian Indigenous Orchids. Volume 1 & 2. Surrey Beatty & Sons in association with The Society for Growing Australian Plants, Chipping Norton, NSW.

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