Pinalia kingii

Large epiphytes or lithophytes with prominent clustered fleshy flattish pseudobulbs, each with several nodes, when young covered by brown papery bracts. Leaves 1-3 per pseudobulb, apical, thin-textured, longer than wide, flat. Racemes relatively long, arising from near the apex of a pseudobulb. Flowers lasting a few days, cup-shaped, with fleshy segments. Lateral sepal bases fused with the column foot. Petals smaller than the sepals. Labellum hinged to the apex of the column foot, 3-lobed, with longitudinal ridges or keels. Column with a long column foot.

Similar Genera

Bryobium, Hymeneria

Significant Generic Characters

Epiphytic/lithophytic orchids; rhizomes very short; pseudobulbs relatively large, fleshy, laterally flattened, multinoded; leaves lasting several seasons, 1-3 per pseudobulb, apical, duplicate, thin-textured but tough, longer than wide, articulated on the apex of the sheathing base, flat; racemes arising from apical and subapical nodes of a pseudobulb, relatively long, multiflowered; peduncle and rhachis circular in cross-section, not winged; flowers lasting a few days, cupulate; perianth segments fleshy, glabrous or  pubescent; lateral sepal bases fused with the column foot; petals smaller than the sepals; labellum hinged to the apex of the column foot; lamina 3-lobed, thin-textured; callus with central keels or ridges.

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Size and Distribution

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A genus of about 20 species distributed in South-east Asia, Malaysia, Philippines, Indonesia and New Guinea with a single non-endemic species in Australia. The native species, Pinalia kingii, is widely distributed in northeastern Queensland between Cape York (1041 S) and Tully (1756 S) near Ayr. State occurrence: Queensland.

Ecology

In Australia Pinalia kingii is restricted to tropical Queensland growing on trees and rocks in brightly lit, humid sites with free air movement. Plants commonly grow on trees overhanging streams, mangroves and other coastal vegetation, in rainforest and in humid areas of open forest. In its habitat the majority of rain falls during the summer wet season (December to March) with the remaining months being drier with sporadic or intermittent rain.

Biology

Pollination: The flowers of Pinalia kingii are generally short-lived but open widely and are insect-pollinated.

Reproduction: Reproduction in Pinalia kingii is solely from seed. Seed dispersal takes 2-4 months after pollination and the capsules develop in an erect position. Apomixis is unknown in the genus.

Seasonal Growth: The plants grow actively during the spring and summer months and are relatively quiescent for the remainder of the year.

Flowering: Flowering occurs mainly between August and October but sporadic flowering can occur at other times.

Hybrids: Natural hybrids involving Pinalia kingii are unknown.

Derivation

Pinalia is ???.

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Botanical Description

Perennial, evergreen, epiphytic or lithophytic herbs, sympodial. Plants glabrous or hirsute. Roots elongate, filamentous, very thin, branched, produced from nodes on the base of the pseudobulb. Rhizome obscure, creeping, branched. Pseudobulbs large, multinoded, fleshy, crowded, relatively long, when young covered by brown scarious bracts. Trichomes present on some floral parts. Aerial growths absent. Leaves lasting several seasons, terminal, 1-3 per shoot, distichous, duplicate, sessile, longer than wide, thin textured, coriaceous, smooth, flat, not grooved or channelled, articulate on the apex of the sheathing base; base sheathing the pseudobulb; margins entire. Inflorescence racemose, elongate, erect to arcuate, arising from an apical or subapical node on a mature pseudobulb, multiflowered. Peduncle shorter than the rhachis, cylindrical in cross-section, glabrous or pubescent, with scattered scarious bracts.  Floral bracts scarious, sheathing the base of the pedicel. Pedicel relatively short, thin, cylindrical, merging with the ovary, glabrous or pubescent. Ovary short, straight, non-twisted, porrect from the pedicel, glabrous or pubescent. Flowers resupinate, cupulate, stalked, lasting a few days, white, cream or yellowish. Perianth segments fleshy, entire, glabrous or pubescent externally. Dorsal sepal free, narrower than the lateral sepalsLateral sepals broader than the dorsal sepal, attached by their bases to the column foot to form a mentum. Petals free, narrower than the sepals. Labellum hinged to the apex of the column foot, markedly dissimilar in size and shape to the sepals and petals, ecalcarate. Labellum lamina 3-lobed; lateral lobes small, erect to spreading, entire; midlobe short to elongate, porrect to decurved; apex entire or emarginate. Spur absent (although flowers can appear saccate). Callus consisting of narrow, median ridges. Nectar absent. Column at an angle to the end of the ovary, lacking free filament and style, fleshy, shorter than the perianth segments, nearly straight. Column wings reduced, lateral, obtuse. Column foot well developed, at a broad angle to the column. Pseudospur absent. Anther terminal, incumbent, small, 8-celled, persistent, attached dorsally by a ligulate claw, smooth, rostrate. Pollinarium present, consisting of pollinia attached by caudicles, sometimes with a rostellum. Pollinia 8 in 2 groups of 4, orange, hard, waxy, stalked, with short thin caudicles. Viscidium small or absent. Rostellum ventral, small. Stigma entire, transverse, concave. Capsules dehiscent, glabrous or hairy, erect; peduncle not elongated in fruit; pedicel not elongated in fruit. Seeds numerous, light coloured, winged.

Taxonomy

Pinalia was recently reinstated as distinct from Eria based on thin filamentous roots, large, laterally flattened pseudobulbs of several nodes, each node with a papyraceous bract, leaves with obscure venation, racemes with a cylindrical peduncle and rhachis, cupulate flowers and narrow column with obscure wings.

Nomenclature

Pinalia Buch.-Ham. Ex D.Don, Prod. Fl. Nep 31, in syn. (1825). 

Type species: Pinalia alba Buch.-Ham.

Infrageneric Taxa: No infrageneric taxa are 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.

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