Porrect to drooping epiphytes with numerous roots and long fibrous leafy stems, unbranched or sparsely branched from near the base. The thick, crowded or well-spaced leathery leaves are arranged in 2 ranks. Inflorescences are long racemes with numerous moderately small flowers. The flowers, which last several days, have a deeply spurred labellum fixed to the base of the column. The column is short and lacks a column foot.
Similar Genera
Significant Generic Characters
Epiphytic orchids; plants large, porrect or drooping; roots numerous, thick; stems long, fibrous, unbranched or sparsely branched from the base; leaves flat, crowded to well spaced, arranged in 2 ranks , much longer than wide, thick, leathery; inflorescence racemose, multiflowered; flowers moderately small, lasting several days; labellum firmly attached to the base of the column; lamina obscurely 3-lobed, with a deep cylindrical basal spur; lateral lobes small; column short, lacking a foot; pollinia 2, sessile on a stipe.
Size and Distribution
A genus of about 20 species distributed in India, Malaysia, Philippines, Indonesia, New Guinea and Australia where there are 2 species, 1 endemic . One species, Robiquetia wassellii, is restricted to the Iron Range (12º38’ S) and McIlwraith Range (13º34’ S) on Cape York Peninsula and the other one, Robiquetia gracilistipes, occurs between the Iron Range and Ingham (18º39’ S). State occurrence: Queensland.
Ecology
The native species of Robiquetia grow on trees in rainforest at low to moderate altitudes, usually in brightly lit situations where there is abundant air movement. The climate is tropical and the majority of rain falls during the summer wet season (December to March), with the remaining months much drier and having sporadic or intermittent rain.
Biology
Pollination: The flowers of the native species of Robiquetia last several days and are insect-pollinated, probably by native bees.
Reproduction: Reproduction in Robiquetia 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: Robiquetia plants grow mainly during the spring and summer months and are relatively quiescent for the remainder of the year.
Flowering: The native species of Robiquetia flower in autumn, winter and spring.
Hybrids: Natural hybrids involving the native species of Robiquetia are unknown.
Derivation
Robiquetia is named after M. Pierre Robiquet, a French chemist who made important chemical discoveries, including caffeine and morphine.
Botanical Description
Perennial, evergreen, epiphytic herbs, monopodial. Roots numerous, thick, elongate, much branched, mainly adherent. Plants large, unbranched or sparsely branched from the base, porrect or drooping. Stem relatively thick, long, fibrous, leafy throughout. Pseudobulbs absent. Trichomes absent. Leaves lasting several seasons, flat, distichous, sessile, crowded to well-spaced, spreading widely, much longer than wide, thick, coriaceous; base sheathing the stem, imbricate with its neighbour, persistent after leaf abscission; margins entire or undulate; apex unequally emarginate. Inflorescence lateral, racemose, multiflowered. Peduncle shorter than the rhachis. Rhachis straight. Floral bracts small, scarious, partly sheathing the base of the pedicel. Pedicel short, merging with the ovary. Ovary short, straight. Flowers resupinate, relatively small, opening sequentially, stalked, lasting several days, cream, green, reddish or yellowish. Perianth segments relatively thick-textured, incurved, porrect or spreading. Dorsal sepal free, subsimilar to the lateral sepals, usually cucullate. Lateral sepals free, subsimilar to the dorsal sepal, usually flanking the labellum. Petals free, narrower than the sepals. Labellum stiffly attached to the base of the column, markedly dissimilar in size and shape to the sepals and petals, calcarate. Labellum lamina obscurely 3-lobed, with a deep basal spur; spur long, cylindrical, often with a medial constriction, narrow, blunt; lateral lobes small, erect, sometimes partly connate to the column; midlobe short, fleshy. Spur basal (see labellum lamina). Callus obscure, consisting of small fleshy protruberances. Nectar unknown. Column short, porrect from the apex of the ovary, lacking free filament and style, fleshy, straight. Column wings small. Column foot absent. Pseudospur absent. Anther terminal, incumbent, 2-celled, persistent, smooth, with a decurved rostrum. Pollinarium present. Pollinia 2, orange, hard, waxy, sessile. Stipe long, often spathulate, sometimes narrow, sometimes hooked. Viscidium small to large, at an angle to the stipe. Rostellum large, broad, bifid. Stigma entire, concave. Capsules dehiscent, elongate, glabrous, porrect; peduncle not elongated in fruit; pedicel not elongated in fruit. Seeds numerous, light coloured, winged.
Taxonomy
Within the Vandeae, Robiquetia is distinguished by large plants; labellum fixed to the column base; lamina with a deep cylindrical basal spur; obscure callus; column without a foot and, 2 sessile pollinia.
Nomenclature
Robiquetia Gaud. in Freycinet, Voy. Monde. Bot. 426 (1829).
Type species: Robiquetia ascendens Gaud.
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.
Garay, L. (1972). On the systematics of the monopodial orchids. Bot. Mus. Leafl. Harv. Uni. 23(4): 149-212.