Corymborkis veratrifolia (PROSEA)
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Introduction |
Corymborkis veratrifolia (Reinw.) Blume
- Protologue: Coll. Orchid.: 125, pl. 42 fig. E, pl. 43 fig. 1 (1859).
- Family: Orchidaceae
- Chromosome number: 2n= 40, 58
Synonyms
Corymborkis longiflora (Hook.f.) O. Kuntze (1891).
Vernacular names
- Malaysia: lelumbah paya, kayu hok (Peninsular)
- Thailand: klon duu (Surat Thani), waan haang hanumaan (Yala), lek naang yong (Pattani)
- Vietnam: dịa lan lá dừa, tản lan.
Origin and geographic distribution
C. veratrifolia is widely distributed in tropical Asia, from India, Sri Lanka and the Andaman Islands, through Indo-China, Thailand and the whole of Malesia (except the eastern Lesser Sunda Islands), to some islands of southern Japan, some of the Caroline Islands, the Solomon Islands, the Santa Cruz Islands, Vanuatu, Fiji, Samoa and to Australia (Cape York Peninsula).
Uses
In Peninsular Malaysia, the juice of fresh leaves is used to cause vomiting as a means of breaking fever, especially in children; the plant is even commonly cultivated for this purpose.
In Africa, C. corymbis Thouars is used in traditional medicine: an infusion of the leaves and a decoction of the roots are taken as a purge.
C. veratrifolia is occasionally cultivated, e.g. in Java, and it has been recorded there as being often found on old graves, perhaps indicating ritual uses.
Properties
The freshly gathered roots have a strong odour of stale urine. C. veratrifolia has been found alkaloid positive, but in small concentration. It is one of the very few plants that survive in large numbers on the forest floor on Christmas Island, where plants are subject to heavy predation by red land crabs. This may be due to the presence of alkaloids.
Botany
A small to large terrestrial herb 40-310 cm tall, with short, sympodially branching rhizome, creeping subterraneously; roots fasciculate and wiry; stems often several from one rhizome, erect, unbranched, leafy. Leaves distichous, but often apparently arranged spirally, the lowermost without blades, narrowly elliptical or narrowly ovate, 15-50(-110) cm × 3-14(-18) cm, plicate with 6-11 main veins, tapering at base into sheathing base, acute or acuminate at apex; petiole absent or very short. Inflorescence an erect to drooping axillary panicle up to 15 cm long, with 2-9 branches, up to 70-flowered, with distichously arranged flowers. Flowers bisexual, 3-merous, white to greenish-white, fragrant; pedicel short, twisted; sepals linear-spatulate to narrowly oblong-spatulate, 1.5-5.5 cm long, about equal in length; petals obliquely linear-spatulate to obliquely obovate, about as long as sepals, labellum spatulate, 1.5-5 cm long, with 2 longitudinal keels embranching the column, and a reflexed apical lamina; column slender and straight, with 2 terminal lateral auricles; rostellum erect, bifid at apex; clinandrium ovate, marginate; anther ovate, with 2 pollinia on long slender caudicle, attached to a peltate viscidium; ovary inferior, cylindrical, stigma with 2 recurved deltoid sidelobes. Fruit a capsule up to 4 cm long, strongly 6-ribbed, crowned by the remnants of perianth and column, containing numerous seeds.
C. veratrifolia can be found flowering throughout the year, but in regions with a distinct rainy season flowering can be limited to this period. The flowers are pollinated by hawk moths, as has been observed in Java.
Corymborkis is a small genus of 6 species, and is pantropical in distribution: 3 species in tropical America, 2 in tropical Africa, and 1 in tropical Asia. It is placed in the subtribe Tropidiinae , and is related to Tropidia , which differs in the often branched stems, terminal inflorescences, spurred or saccate labellum and shorter column. C. veratrifolia is a variable species, especially in the size of the floral parts. Var. lauterbachii (Schlechter) F.N. Rasm. is distinguished from var. veratrifolia by narrower leaves and is endemic to New Guinea.
Ecology
C. veratrifolia prefers shaded and moist localities on the floor of evergreen forest, from sea-level up to 2000 m altitude. It has also been recorded from secondary forest. It is locally common, sometimes even abundant (e.g. on Christmas Island), but usually occurs scattered in small clumps.
Genetic resources
C. veratrifolia has a very large area of distribution and does not seem to be endangered. Breeding activities are not known to exist.
Prospects
As far as is known, C. veratrifolia has never been subject to detailed phytochemical investigations or to testing for pharmacological properties. Research seems worthwhile judging from the uses in traditional medicine in South-East Asia and from medicinal applications of a related species in Africa. C. veratrifolia has been recommended for cultivation as an ornamental, suitable for shaded spots in tropical gardens.
Literature
121, 222, 771.
Other selected sources
62, 120, 731.
Main genus page
Authors
R.E. Nasution
