Evergreen terrestrials with fleshy conical pseudobulbs each with a single large stalked leaf. The unbranched inflorescence usually arises on a separate growth from the leaf-bearing pseudobulbs and carry small to relatively large, yellowish, brownish, red or purple stalked flowers in a terminal raceme. The sepals and petals are narrow or triangular with the lateral sepals attached by their bases to the column foot. The labellum, which usually lacks a basal spur, is unlobed or 3-lobed with prominent longitudinal keels on the upper surface.
Significant Generic Characters
Evergreen autotrophic terrestrial orchids (rarely epiphytic); pseudobulbs fleshy, emergent, single-noded; leaf solitary, petiolate, flat, smooth or plicate, articulate on the apex of the pseudobulb; inflorescence on a separate growth from the pseudobulbs, racemose, terminal; flowers resupinate, yellowish, brownish, red or purple; dorsal sepal free; lateral sepal bases fused with the column foot to form a short mentum; petals free; labellum usually 3-lobed, with longitudinal keels; column with a short foot; pollinia usually 8 (rarely 6), usually in 4 pairs, unequal.
Size and Distribution
A genus of about 13 species distributed in tropical parts of Asia, South-east Asia, Japan, Malaysia, Philippines, Indonesia, New Guinea and Australia where there is a single non-endemic species, Tainia trinervis, that is reliably known only from a single locality. State occurrence: Queensland.
Ecology
Tainia trinervis grows in dense lowland rainforest, usually in the ground, occasionally in accumulations of litter on boulders.
Biology
Pollination: The flowers of Tainia trinervis are insect-pollinated but the vector(s) is unknown.
Reproduction: Reproduction in Tainia trinervis is solely from seed. The period of seed development and capsule dehiscence is unknown. Apomixis is unknown in the genus.
Seasonal Growth: Little is known about the seasonal growth of Tainia trinervis but it is probably tied in with the wet season.
Flowering: Tainia trinervis flowers between September and November.
Hybrids: Natural hybrids involving species of Tainia are unknown.
Fire: Tainia trinervis grows in high rainfall lowland rainforest where fires are unknown.
Derivation
The name Tainia is derived from the Greek tainia, fillet, an obscure reference possibly referring to the narrow leaves and elongated petioles or the longitudinal keels on the labellum.
Botanical Description
Perennial geophytic herbs, rarely epiphytic, autotrophic, evergreen, sympodial. Plants glabrous. Flowering and non-flowering plants monomorphic. Roots filamentous, fleshy, solitary from the base of a pseudobulb, unbranched. Stems creeping,with membranaceous bracts at each node, sometimes persisting as fibres. Pseudobulbs elongate-conical, single-noded, fleshy, erect, crowded or well-spaced, when young covered with a single scarious bract. Trichomes absent. Leaf 1-per shoot, terminal, flat, smooth or plicate, petiolate, articulate on the top of the pseudobulb. Venation acrodromus without included veinlets. Inflorescence a raceme, usually terminating a separate growth, rarely from a node of the previous shoot, alternating with the sterile shoots, the base swollen, few-many-flowered. Peduncle much longer than the rhachis, with scattered tubular or semi-sheathing bracts. Rhachis shorter than the peduncle, straight. Floral bracts small, often triangular, semi-sheathing. Pedicel short, merging with the ovary. Ovary straight, narrow. Flowers resupinate, uncrowded, small to moderately large, yellowish, brownish, red or purple, lasting a few days, opening simultaneously or sequentially. Sepals and petals entire, narrow or triangular. Dorsal sepal free, similar to the lateral sepals, erect to recurved. Lateral sepals fused by their bases to the column foot to form a short mentum, similar to the dorsal sepal, widely divergent. Petals free, usually porrect and held close to the column. Labellum hinged to the apex of a column foot by a short claw, markedly dissimilar in size and shape to the sepals and petals, shortly calcarate or ecalcarate. Labellum lamina unlobed or 3-lobed; lateral lobes, if present, relatively small, erect, often triangular; midlobe short to long, narrow to broad, porrect to decurved. Spur, if present, short, shallow. Callus consisting of longitudinal keels sometimes running the length of the labellum, straight or sinuate, smooth or papillate. Nectar unknown. Column porrect from the end of the ovary, slender, lacking free filament and style. Column wings prominent, projecting. Column foot small. Pseudospur absent. Anther dorsal, entire or bilobed, 2-celled, channelled between the cells, rostrate. Pollinarium absent. Pollinia 8, rarely 6, in 4 pairs, subequal, 1 small proximal pair and 1 large distal pair in each anther cell, attached by short caudicles. Viscidia absent. Rostellum small. Stigma convex, entire. Capsules dehiscent, glabrous, erect; peduncle not elongated in fruit; pedicel not elongated in fruit. Seeds numerous, light coloured, winged.
Taxonomy
The native species was originally recorded as T. parviflora Schltr but that species was reduced to a synonym of T. trinervis (Blume) Rchb.f. (see Turner 1992).
Notes
Although sometimes listed as being relatively widespread, Tainia trinervis has proved to have a very restricted distribution in Australia where it is reliably recorded from only a single locality.
Nomenclature
Tainia Blume, Bijdr., 6: t.5, fig. 48; 7: 354 (1825). Type species: Tainia speciosa Blume.
Infrageneric Taxa: There has been no formal division of Tainia.
References
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.
Turner, H. (1992). A revision of the orchid genera Ania Lindley, Hancockia Rolfe, Mischobulbon Schltr. and Tainia Blume. Orchid Monographs 6: 43-100.