Projecting to pendulous small unbranched or sparsely branched epiphytes with numerous relatively thin roots and a short thin fibrous leafy stem. The small, crowded, relatively broad leaves are arranged in 2 ranks, sometimes appearing fan-like. Inflorescences are short to relatively long, thin or thickened near the middle, unbranched. The small uncrowded fragrant flowers face the end of the raceme and are mainly greenish. They have relatively narrow projecting or incurved segments and a stiffly attached labellum with a deep cylindrical basal spur which lacks any internal structures. The column is short without a column foot.
Similar Genera
Significant Generic Characters
Epiphytic orchids; plants small, unbranched; stems thin, fibrous; leaves crowded, thinly coriaceous, in 2 ranks, sometimes fan-like, longer than wide; racemes thin or thickened in the middle; flowers small, facing the raceme apex, lasting several days, fragrant; perianth segments thick-textured; sepals subsimilar; petals slightly shorter than the sepals; labellum firmly attached to the column base; lamina 3-lobed, with a basal spur; spur deep, cylindrical, without any internal callus structures; column short, without a foot, winged; pollinia 4, sessile on a stipe, in 2 unequal pairs.
Size and Distribution
A small genus of about 8 species in Indonesia, New Guinea and Australia where there are 2 endemic species (one species possibly extending to New Guinea). In Australia the genus is distributed disjunctly in Queensland between Weipa (12º37’ S) and Bundaberg (24º52’ S). State occurrence: Queensland.
Ecology
Saccolabiopsis armitii grows on shrubs and trees in coastal scrubs and drier types of rainforest, in some areas extending well inland from the coast. Saccolabiopsis rectifolia grows on trees in sheltered gorges and overhanging streams at low altitudes.
Biology
Pollination: The flowers of Saccolabiopsis last many days and are pollinated by native bees.
Reproduction: Reproduction in Saccolabiopsis 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 Saccolabiopsis grow mainly during the spring and summer months and are relatively quiescent for the remainder of the year.
Flowering: The native species of Saccolabiopsis flower from winter to early summer.
Hybrids: Natural hybrids involving native species of Saccolabiopsis are unknown.
Derivation
The name Saccolabiopsis is based on a resemblance to the genus Saccolabium; (-opsis) resemblance.
Botanical Description
Perennial, evergreen, epiphytic herbs, monopodial. Roots thin, elongate, straight or convolute, mostly adherent. Plants small, porrect or pendulous. Stem short, fibrous, rarely branched. Pseudobulbs absent. Trichomes absent. Leaves lasting several seasons, porrect or spreading, distichous, sessile, longer than wide, narrow, mostly flat, thinly coriaceous, smooth; base sheathing the stem, usually persistent after leaf abscission; margins entire. Inflorescence lateral, racemose, arcuate or pendulous, multiflowered. Peduncle shorter or subsimilar to the rhachis, sometimes thickened distally, with few imbricate scarious bracts. Rhachis straight, sometimes thickened proximally. Floral bracts scarious, sheathing the base of the pedicel. Pedicel short, thin, merging with the ovary. Ovary short, straight. Flowers resupinate, relatively small, stalked, opening sequentially, lasting several days, greenish, fragrant. Perianth segments moderately thin-textured, mainly incurved. Dorsal sepal free, subsimilar to the lateral sepals. Lateral sepals free, subsimilar to the dorsal sepal, flanking the labellum. Petals free, slightly smaller 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 fleshy, dominated by a basal spur, 3-lobed; spur deeply saccate, cylindric, straight or curved, without any internal callus structures; lateral lobes short, broad, blunt, free, sometimes vestigial; midlobe short, concave or convex. Spur present (see above). Callus absent or obscure. Nectar present (?). Column short, porrect from the apex of the ovary, lacking free filament and style, fleshy, nearly straight. Column wings short, narrow. Column foot absent. Pseudospur absent. Anther terminal, incumbent, 2-celled, persistent, smooth, with a narrow curved rostrum. Pollinarium present. Pollinia 4 in 2 appressed pairs, unequal, orange, hard, waxy, sessile. Stipe well-developed, long, narrow, sometimes widened distally. Viscidium present, small, at an angle to the stipe Rostellum ventral, elongate, bifid. Stigma entire, concave. Capsules dehiscent, glabrous, porrect; peduncle not elongated in fruit; pedicel not elongated in fruit. Seeds numerous, light coloured, winged.
Taxonomy
Within the Vandeae, Saccolabiopsis is distinguished by small, thick-textured flowers facing the raceme apex, 3-lobed labellum with a deep cylindrical spur without any internal callus structures, winged column without a foot and, 4 sessile pollinia in 2 unequal pairs.
Nomenclature
Saccolabiopsis J.J.Smith, Bull. Jard. Bot. Buitzenorg 26: 93 (1918).
Type species: Saccolabiopsis bakhuizenii J.J.Smith.
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.