Terrestrials, either leafless or with a few leaves, the stems either developed into pseudobulbs or as irregular-shaped subterranean rhizomes. Leaves if present are usually long, narrow, smooth or pleated and often stalked at the base. Inflorescences are usually long, unbranched and with small to large often colourful flowers. The labellum, which is stiffly hinged to the base of the column or apex of the column foot, usually has large lateral lobes, a projecting midlobe and a ridged or keeled callus. The column is long and narrow, usually with a column foot but sometimes without.
Similar Genera
Significant Generic Characters
Terrestrial orchids, sometimes leafless saprophytes; stems either pseudobulbous or rhizomatous, emergent or subterranean, multinoded; leaves, when present, stalked, smooth or plicate; inflorescence terminal or lateral from a basal node, racemose (paniculate in some exotic species); flowers small to large, short-lived or lasting many days; sepals and petals subsimilar or dissimilar; labellum stiffly hinged to the base of the column or apex of the column foot; lamina unlobed or 3-lobed, with or without a short saccate basal spur; lateral lobes, if present, large, erect; midlobe well-developed, narrow or broad; callus ridged or keeled, glabrous or hairy; column elongate, with or without a foot; pollinia 2 (? or 4), sessile on a short stipe.
Size and Distribution
A genus of about 250 species widely distributed in tropical and subtropical areas with 6 species occurring in Australia, 3 endemic, 2 non-endemic and I naturalised in the Northern Terrirtory. One native species occurs in the Kimberley Region of northern Western Australia, northern parts of the Northern Territory and northern Queensland and the others are distributed disjunctly in Queensland between the Iron Range and Rockhampton with reports of the genus also occurring in the vicinity of Maryborough in southeastern Queensland. State occurrence: Western Australia, Northern Territory, Queensland.
Ecology
Habitats include rainforest, rainforest margins, open forest and grassland. Eulophia zollingeri, a leafless saprophyte, grows close to decaying wood such as stumps and fallen trees in rainforest or wet forest.
Biology
Pollination: The flowers of Eulophia pelorica are self-pollinating and may even be apomictic. The other native species are apparently insect-pollinated but the vectors are unknown.
Reproduction: Reproduction in Eulophia is solely from seed. Seed dispersal takes 2-4 months from pollination and the capsules develop in a pendant position.
Seasonal Growth: Plants of Eulophia zollingeri are leafless with the inflorescence above ground during the wet season. Plants of Eulophia pelorica are evergreen and grow mainly during the spring and summer months. The other native species are deciduous for short periods during the dry season.
Flowering: Most native species flower in winter and spring but Eulophia zollingeri flowers in summer.
Hybrids: Natural hybrids involving the native species of Eulophia are unknown.
Fire: The deciduous species grow in fire-prone habitats and the plants reshoot after fire but there is no evidence of fire stimulation.
Derivation
The name Eulophia is derived from the Greek eu, well and lophos, plume, apparently in reference to the callus on the labellum of some species.
Botanical Description
Perennial, leafless or leafy geophytic herbs, deciduous, sympodial. Plants glabrous. Roots filamentous. Stems consisting of several nodes, either regularly swollen and developing as emergent pseudobulbs or occurring as irregularly shaped subterranean rhizomes. Trichomes either absent or present on the labellum. Leaves present or absent, 1-2 per shoot, either deciduous annually or lasting several seasons, flat, conduplicate and smooth or plicate, sessile or stalked. Venation unknown. Flowering and non-flowering plants monomorphic. Inflorescence racemose or paniculate (non-Australian), either terminal on a subterranean rhizome or lateral from the basal node of a pseudobulb, multiflowered. Peduncle longer than the rhachis, with few-several tubular or semi-tubular sterile bracts. Rhachis straight, shorter than the peduncle. Floral bracts narrow, scarious, partially sheathing the base of the pedicel. Pedicel short to moderately long, thin, merging with the ovary. Ovary short, straight. Flowers resupinate, small to large, lasting 2-several days, opening sequentially, white, cream or pale green (rarely deep red as in Eulophia zollingeri), pedicellate, scentless (Eulophia pelorica), fragrant or strongly scented (Eulophia zollingeri). Perianth segments thin to fleshy, spreading or remaining partially closed (Eulophia pelorica). Dorsal sepal free, similar, subsimilar or smaller than the lateral sepals. Lateral sepals free or attached by their bases to the column foot, similar, subsimilar or larger than the dorsal sepal. Petals subsimilar to or smaller than the sepals, often asymmetric. Labellum free, either stiffly hinged to the column base or the apex of the column foot, markedly dissimilar in size and shape to the sepals and petals, calcarate or ecalcarate. Labellum lamina unlobed or 3-lobed, some species with a short basal spur, others with a pseudospur formed by the column foot, basal labellum margins and bases of the lateral sepals; spur, if present, short, shallowly saccate; lateral lobes, if present, large, erect; midlobe porrect to recurved, narrow or dilated. Spur (see labellum lamina). Callus variable, consisting of keels, ridges or calli, glabrous or hirsute. Nectar unknown. Column porrect from the end of the ovary or at an angle, narrow, elongate, straight or curved, lacking free filament and style, fleshy. Column wings greatly reduced, terminal. Column foot either absent (Eulophia pelorica) or short to long, variably angled to the column base. Pseudospur present or absent (see labellum lamina). Anther terminal, incumbent, 2-celled, persistent, smooth, with a short rostrum. Pollinarium present. Pollinia 2, notched (sometimes recorded as 4 pollinia), hard, waxy, sessile. Stipe short, narrow or broad. Viscidium variable in size. Rostellum small, entire. Stigma entire, small to large, concave. Capsules dehiscent, glabrous, pendant; peduncle not elongated in fruit; pedicel not elongated in fruit. Seeds numerous, light coloured, winged.
Taxonomy
As currently interpreted Eulophia is polyphyletic and in need of a detailed morphological and molecular study.
Notes
Eulophia graminea, a species that is widespread in Asia, has become naturalised on road verges, median strips and gardens in Darwin.
Nomenclature
Eulophia R.Br. ex Lindl. in Edwards’s, Bot. Reg. 8: t.686 (1823) (nom. cons.). Type species: Eulophia guineensis Lindl. (type cons.)
Graphorkis Thouars, Nouv. Bull. Sci. Philom. Paris 1: 318 (1809) (nom. rejected vs. Eulophia). Type species: Limodorum scriptua Thouars.
Lissochilus R.Br. in Edwards’s, Bot. Reg. 7: t.573 (1821) (nom. rejected vs. Eulophia). Type species: Lissochilus speciosus R.Br.
Cyrtopera Lindl., Gen. sp. Orchid pl. 189 (1833). Type species: Cyrtopera woodfordii Sims
Infrageneric Taxa: No satisfactory infrageneric treatment of Eulophia is available.
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.
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.