Epiphytes or lithophytes with creeping branched rhizomes anchored by filamentous roots and with short, conical, single-noded pseudobulbs widely spaced and erect on the rhizomes. Each pseudobulb has a single, terminal, petiolate leaf that is longer than wide, flat and firm-textured. The flowers, which are borne singly on long thin scapes, are relatively large, with the sepals ending in filiform tails. The dorsal sepal is smaller than the lateral sepals and has hairy margins. The bases of the lateral sepals are fused together and to the column foot. The labellum, which is three-lobed and fleshy, is hinged to the apex of the column foot and delicately balanced. The flowers last several days.
Significant Generic Characters
Epiphytic/lithophytic orchids; plants appressed; rhizomes creeping; roots filamentous; pseudobulbs conical, single-noded; leaf solitary, petiolate; inflorescence arising from rhizome nodes; scapes long, thin; flowers solitary; sepals with filiform or clavate tails; dorsal sepal smaller than the lateral sepals, with hairy margins; lateral sepal bases fused together and to the column foot; labellum delicately hinged to the apex of the column foot; labellum lamina three-lobed, fleshy.
Size and Distribution
A genus of c. 20 species, the majority occurring in New Guinea, with others distributed in Malaysia, Philippines, Indonesia, Borneo, New Guinea, Solomon Islands, Vanuatu, New Caledonia and Australia, including the Torres Strait Islands. A single widespread species, Ephippium masdevalliaceum (Kraenzl.) M.A.Clements and D.L.Jones, extends to northern Queensland where it occurs in the headwaters of the Jardine River near the top of Cape York Peninsula, and on Moa Island in the Torres Strait. State occurrence: Queensland (including Moa Island).
Ecology
Ephippium masdevalliaceum grows in relatively open lowland rainforest where there is bright light, relatively high humidity and free air movement. The climate is tropical and the majority of the rain falls during the summer wet season (December to March) and the remaining months are much drier, with sporadic or intermittent rain.
Biology
Pollination: The flowers of Ephippium masdevalliaceum last for 2-3 days and are insect-pollinated. Small flies are the most likely vector, these being attracted to the flowers to feed on nectar that gathers on the labellum.
Reproduction: Reproduction in Ephippium masdevalliaceum is solely from seed. Seed dispersal in these orchids takes 3-6 months after pollination and the capsules develop in an erect position. There is no increase in the length of the peduncle or pedicel during this process. Apomixis is unknown in the genus.
Seasonal Growth: The plants grow strongly during the summer months and for a period after the wet, and are relatively quiescent for the remainder of the year.
Flowering: Flowering is sporadic but occurs mainly in winter and spring.
Hybrids: Natural hybrids involving Ephippium masdevalliaceum are unknown.
Derivation
The generic name Ephippium is derived from ephippion, saddle and apparently refers to the saddle-shaped labellum of the type species.
Botanical Description
Perennial, evergreen, epiphytic or lithophytic herbs, sympodial. Roots filamentous, produced mainly from nodes at the base of the pseudobulbs. Rhizomes appressed to the host, well developed, sturdy, creeping, much branched, covered by closely sheathing, imbricate, scarious bracts. Pseudobulbs erect, in-line, widely spaced, single-noded, ovoid to conical. Trichomes present or absent. Leaves petiolate, 1- per shoot, terminal on a pseudobulb, not sheathing at the base, flat, longer than wide, smooth, firm-textured; apex unequally emarginate. Inflorescence arising from a node on the rhizome, erect, 1-flowered. Peduncle much longer than the pedicel, with 2-3 tubular, sheathing sterile bracts. Floral bract small, sheathing the base of the pedicel. Pedicel much shorter than the peduncle, straight or curved, merging with the ovary. Ovary elongate, straight, smooth, merging with the pedicel. Flowers resupinate, pedicellate, facing outwards, nodding in bud, lasting a few days, dull coloured (redddish or purplish). Perianth segments thin textured. Dorsal sepal free, smaller and of a different shape to the lateral sepals, not hooded; margins hirsute; apex aristate or setiferous. Lateral sepals much larger than the dorsal sepal, connate at the base and their bases partially fused with the column foot. Petals free, much smaller than the sepals; margins hairy. Labellum attached in from its base, hinged by a short claw to the apex of the column foot, delicately balanced, markedly dissimilar in shape to the sepals and petals, ecalcarate. Labellum lamina three-lobed, fleshy, curved; margins entire; apex filiform, entire. Callus obscure, consisting of a shallow basal channel. Nectar present. Column lacking free filament and style, short, straight. Column wings present, ventral with linear apical stelidia. Column foot well developed, strongly incurved. Anther terminal, incumbent, 2-celled, deciduous, basifixed, smooth, erostrate. Pollinarium absent. Pollinia 4 in 2 pairs, crescentic, yellow or orange, hard, waxy. Viscidium absent. Rostellum ventral, transverse. Stigma entire, vertical, concave. Capsules dehiscent, glabrous; peduncle not elongated in fruit; pedicel not elongated in fruit. Seeds numerous, light coloured, winged.
Taxonomy
Ephippium, previously treated as a section within Bulbophyllum, was recently raised to generic rank (Clements and Jones 2002).
Nomenclature
Ephippium Blume, Bijdr. 308 (1825). Type species: non designatus.
Bulbophyllum Thouars sect. Ephippium Schltr.
Infrageneric Taxa: No infrageneric taxa are currently recognised.
References
Clements, M.A. and Jones, D.L. (2002). Nomenclatural changes in the Australian and New Zealand Bulbophyllinae and Eriinae (Orchidaceae). Orchadian 13(11): 498-501.
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.
Lavarack, P.S. and Gray, B. (1985). Tropical Orchids of Australia. Thomas Nelson, Melbourne.
Schlechter, R. (1982). The Orchidaceae of German New Guinea (English translation by R.S. Rogers, H.J. Katz and J.T. Simmons). Australian Orchid Foundation, Melbourne.
Vermuelen, J.J. (1991). Orchids of Borneo. Vol. 2 Bulbophyllum. Toihaan Publishing Coy, Kota Kinabalu.