Fruit-fly Orchids
Epiphytes or lithophytes with creeping branched rhizomes anchored by filamentous roots and short single-noded pseudobulbs widely spaced and partially appressed on the rhizomes. Each pseudobulb has a single large flat, thick, leathery terminal leaf that is longer than wide. The flowers are borne singly on inflorescences that arise from nodes along the rhizome. The flowers, which are relatively large and fleshy, face upwards and have a fruity scent. The petals are narrower than the sepals and the labellum, which is 3-lobed and fleshy, is hinged to the apex of the column foot and delicately balanced. The flowers are short-lived, lasting about 24 hours and turn pink-red as they age.
Significant Generic Characters
Epiphytic/lithophytic orchids; plants appressed; roots filamentous; rhizomes creeping; pseudobulbs single-noded, partially appressed on the rhizomes; leaf single, large, leathery; inflorescences from rhizome nodes; flowers solitary, short-lived, facing upwards, fleshy, with a fruity scent; petals narrower than the sepals; labellum delicately hinged to the apex of the column foot; labellum lamina 3-lobed, fleshy.
Size and Distribution
A genus of 15-20 species distributed in South-East Asia, Malaysia, Philippines, Indonesia, New Guinea, Solomon Islands and Australia. A single non-endemic species, Carparomorchis baileyi (F.Muell.) M.A.Clem. and D.L.Jones, occurs in Queensland between Cape York and Ayr and on some islands of the Torres Strait. It also extends to New Guinea. State occurrence: Queensland (including Moa and Dauan Island).
Ecology
Species of Carparomorchis commonly grow in lowland rainforest but some species extend into the mountains to about 800 m alt. They grow on trees or rocks in situations of bright light, high humidity and free air movement. Carparomorchis baileyi, which is very widespread and generally abundant in northern Queensland, grows on trees and rocks in a wide range of habitats including mangroves, rainforest, monsoonal vine thickets, gallery forest and humid sheltered areas in open forest and woodland. Plants of Carparomorchis baileyi occur in tropical regions where the majority of the rain falls during the summer wet season (December to March) and the remaining months are much drier, with sporadic or intermittent rain.
Biology
Pollination: The flowers of Carparomorchis baileyi last about 24 hours, after opening early in the morning, but are only receptive to pollinators in the first few hours after opening. The pollination process was observed by D.L.Jones during a wet season field trip to Heathlands on Cape York Peninsula. The flowers release a strong fruity odour that attracts native fruit flies, sometimes in numbers. These insects spend long periods on the flowers lapping nectar and wandering about. If they move onto the labellum it first tips backwards with their weight and as they move forwards, the point of balance of the labellum alters and the insect is tipped forwards against the column. Here it is imprisoned for a period between the labellum and column wings, struggling until it gains freedom, usually with pollen attached to its thorax. Sometimes smaller flies become trapped during this process and perish in the flower.
Reproduction: Reproduction in Carparomorchis is solely from seed. Seed dispersal of Carparomorchis baileyi takes 4-6 months after pollination and the capsules develop in an erect position. There is no increase in the length of the peduncle or pedicel during this process, although the pedicel thickens. Apomixis is unknown in the genus.
Seasonal Growth: The plants grow strongly during the summer months and for a period after the wet and are relatively quiescent for the remainder of the year.
Flowering: Flowering occurs mainly in the summer months.
Hybrids: Natural hybrids involving Carparomorchis baileyi are unknown.
Derivation
The generic name Carparomorchis is derived from the Greek karpos, fruit, aramatos, smell and Orchis another genus of Orchidaceae, but also a general term for orchids. The flowers of this genus have strong fruity odours.
Botanical Description
Perennial, evergreen, epiphytic or lithophytic herbs, sympodial. Plants glabrous. Roots filamentous, produced from along the rhizomes and the base of a pseudobulb. Rhizomes appressed to the host, well developed, sturdy, creeping, much branched, covered by closely sheathing, imbricate, scarious bracts. Pseudobulbs partially appressed to the rhizome, in-line, widely spaced, single-noded, ovoid, conical or shortly cylindric, fibrous. Leaves sessile to subsessile, 1- per shoot, terminal on a pseudobulb, not sheathing at the base, flat, longer than wide, smooth, thick, coriaceous; apex emarginate. Inflorescence arising from a stem node, 1-flowered, erect. Peduncle much shorter than the pedicel, with 3-4 closely sheathing, imbricate, scarious sterile bracts at the base. Floral bract tubular, small, sheathing the base of the pedicel. Pedicel longer than the peduncle, erect, widening distally and merging with the ovary. Ovary elongate, straight, smooth, merging with the pedicel. Flowers resupinate, pedicellate, facing upwards, short-lived (24 hours), dull coloured (white, cream or yellowish with red or purplish spots, ageing pinkish), with a fruity fragrance. Perianth segments fleshy, curved upwards distally. Dorsal sepal free, slightly larger and of a different shape to the lateral sepals; apex cymbiform. Lateral sepals slightly smaller than the dorsal sepal, falcate, attached by their bases to the column foot. Petals free, shorter and narrower than the sepals. Labellum hinged by a short claw to the apex of the column foot, delicately balanced, markedly dissimilar in size and shape to the sepals and petals, ecalcarate. Labellum lamina more or less ligulate, three-lobed, thick and fleshy, curved; lateral lobes basal, suberect; margins entire; apex entire or emarginate. Callus obscure, consisting of a shallow basal channel. Nectar present. Column lacking free filament and style, short, straight. Column wings present, ventral and with tooth-like or triangular apical stelidia. Column foot well developed, curved upwards at the apex. Anther terminal, incumbent, 2-celled, persistent, basifixed, smooth or papillate, erostrate. Pollinarium absent. Pollinia 4 in 2 pairs, triangular, yellow or orange, hard, waxy. Viscidium absent. Rostellum ventral, transverse. Stigma entire, transverse, concave. Capsules large, dehiscent, glabrous, erect; peduncle not elongated in fruit; pedicel not elongated in fruit. Seeds numerous, light coloured, winged.
Taxonomy
Carparomorchis, previously treated as a section within Bulbophyllum, was recently redescribed at generic rank (Clements and Jones 2002).
Nomenclature
Carparomorchis M.A.Clem. and D.L.Jones, Orchadian 13(11): 499 (2002). Type species: Carparomorchis macrantha (Lindl.) M.A.Clem. and D.L.Jones.
Bulbophyllum Thouars sect. Stenochilus J.J.Sm., Bull. J. Bot. Buitenz. (ser. 2) 13: 33 (1914).
Infrageneric Taxa: No infrageneric taxa are currently 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.
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.