Terrestrial, rarely epiphytic, herbs with hairy tubers or long fleshy roots. Stem unbranched. Leaves several-many, lanceolate, ovate oblong or elliptic, sheathing at the base, arranged along stem or clustered at the base or in the middle, or with 1-2 basal leaves appressed to the ground and the cauline leaves sheath-like. lnflorescence terminal, one- to many-flowered. Flowers usually resupinate, green and/or white, rarely with a yellow, pink, or red labellum. Sepals usually free, the dorsal sepal often forming a hood with the petals; lateral sepals spreading or reflexed. Petals entire, two-lobed or bifid. Labellum entire or three-lobed, spurred at base; the side lobes sometimes clivided; the spur long or short, slender or saccate, often inflated at apex. Column long or short; anther erect or reclinate, the loculi either adjacent or separated by a U-shaped connective; anther canals long or short, almost always adnate to side lobes of rostellum; lateral appendages two, sometimes two-lobed; pollinaria two, each with a sectile pollinium, long or short caudicle, and a small, naked viscidium; stigmatic processes two, long or short, usually free but sometimes joined in lower part to rostellum. (PC).
Species of the widespread genus, Habenaria, are usually terrestrial orchids that perennate by means of underground tubers. More rarely they are epiphytic herbs, such as H. procera Lindl., which often grows on oil palm trees (Elaeis guineensis A. Cheval.) in western Africa and is typically found among ferns and mosses in lowland rain forest in eastern Africa (Summerhayes 1968). Throughout the range of the genus, Habenaria species frequently grow in damp or wet habitats including marshes, bogs, water meadows, seasonally flooded grasslands ('dambos' and 'vleis' in Africa), seepage slopes and wet flushes on hillsides, riverbank habitats, swamp forest, and tropical wet evergreen forest (Holttum 1964; Ohwi 1965; Summerhayes 1968; Miller 1978; Polunin and Stainton 1984; la Croix and Cribb 1995). Some species even grow in standing or slowly running water. Other members of the genus inhabit drier areas such as grassland and dry deciduous woodland (la Croix and Cribb 1995). A few African species are reported to occur on old termite mounds (e.g. H. armatissima Rchb.f.), and other Habenaria orchids frequently grow in stoney soil or shallow soil among rocks, which may be either wet or dry. The underlying substrate from areas in which Habenaria species grow includes limestone, granite, quartzite, and laterite (Holttum 1964; la Croix and Cribb 1995). Soil types range from peaty to sandy (Summerhayes 1968; la Croix and Cribb 1995).
Habenaria species growing in open or exposed habitats, such as montane grasslands, receive high light-levels, but others are shade-tolerant plants that occur in deciduous or evergreen woodlands throughout the range of the genus. In Africa Habenaria grows in a variety of vegetation types including Brachystegia (Fabaceae), Uapaca (Euphorbiaceae), and Cryptosepalum (Fabaceae) woodlands, mopani bush, Syzigium (Myrtaceae) thickets, Miombo woodland, and Eucalyptus (Myrtaceae) and pine plantations (la Croix and Cribb 1995). ln Papua New Guinea, Habenaria species are common in the Morobe lowland rainforests growing in the deep litter of the forest floor (Millar 1978), and in the United States H. quinqueseta (Michx.) Sw. occurs in pine and other woods in the southern states of America (Rickett 1966).
Habenaria species grow at a wide range of elevations from lowlands to high montane areas. For example, in South Africa Habenaria Lindl. occurs only in coastal bush on stabilized sand-dunes (Schelpe 1966), and in Japan species such as H. sagittifera Rchb.f. are typically found in bogs and wet grasslands at low elevations (Ohwi 1965). Other species are mountain plants. Habenaria pectinata D. Don occurs in the Himalayas up to 3000 m (Hooker 1894; Polunin and Stainton 1984) and in Uganda, Kenya, and Ethiopia at 2200-3300 m in upland moorland. Habenaria bracteosa Hochst. ex A. Rich., a mountain-forest species from eastern Africa, grows above the forest zone at 2200-3600 m (Summerhayes 1968). Some species grow across a wide elevational range, for example the widespread tropical African orchids H. welwitschii Rchb.f. and H. arianae D. Geerinck, which grow in grasslands at elevations of 0-2000 m and 600-2300 m, respectively.
Flowering of Habenaria usually takes place from July to October or October to January in different parts of Asia (Ohwi 1965; Dassanyake 1981; Polunin and Stain ton 1984), from August to January in the United States (Rickctt 1966), and between October and April (to June) in tropical Africa (la Croix and Cribb 1995). Fruit-set data have been colleccted in tropical Africa (la Croix and Cribb 1995), and levels of reproductive success could be expected to be high given that members of the genus are nectariferous (Neiland and Wilcock 1998). New tubers probably begin to form following flowering and are the means by which the plants survive the dry season in some regions. Tubers may also allow vegetative spread. For example, la Croix and Cribb (1995) noted that H. nyikensis G. Williamson, a species endemic to Malawi, rarely flowers but does form large colonies in open montanc grassland and Brachystegia woodland habitats. Mycorrhizal associations have been investigated for some Habenaria species, such as H. rariflora from southern India, the root systems of which were heavily infected with mycorrhiza (Raja et al. 1996). At least one species, H. saprophytica J. Bosser & P. J. Cribb, is reported to be achlorophyllous (Bosser and Cribb 1996).
Habenaria includes both rare and common species. Some are endemics with restricted distributions, for example H. pubipetala Summerh. which is confined to six localities in Malawi (la Croix 1994). Others have become scaree through over-collection, such as H. camea N. E. Br. in Malaysia (Holttum 1964). In China, H. delavayi Finet and H. dentata Schltr. are collected for use in herbal medicine (Chen and Tang 1982). Cribb noted that H. taeniodema Summcrh. from the highlands of Ethiopia is possibly on the verge of extinction because of threats to its scrubland habitat and coLlection of the plant itself (IUCN Orchid Specialist Group 1996). Pradhan (lUCN Orchid Specialist Group 1996) listed five Habenaria species as among the most threatened orchids in India, either because of their localized distribution (e.g. H. pseudophrys King & Pantl.) or because thay have not been recorded for a long time (e.g. H. pachycaulon Hook.f.). Cadet (1989) suggested that three endangered Habenaria species should be protected on the island of Reunion in the Mascarenes. (RN).
A genus of about 600 species, in tropical and subtropical regions of Old and New World. (PC).
Orchidaceae, I. la Croix & P.J. Cribb. Flora Zambesiaca 11:1. 1995
Orchidaceae, V. S. Summerhayes. Flora of Tropical East Africa. 1968
M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS
A few species are cultivated, notably the Asiatic H. rhodocheila, which has a red or yellow lip.
Lawler (1984) listed several uses for Habenaria species. Some species have been used as charms. Habenaria dives Rchb.f., H. dregeana LindJ., and H. epipactidea Rchb.f. were used as charms in South Africa, the first as a death charm; tubers are mixed with food and the victim then expected to waste away (Rayner 1977). The tubers of H. walleri Rchb.f. in Malawi have been used as food, prepared in the form of a jelly, which is boiled with salted water and served with peanuts as a side dish (Williamson 1955). Habenaria acuminata Thw. ex Trimen. and H. commelinifolia Lindl. are both used as food in India, the latter boiled to make a gruel (Duggal 1972; Usher 1974). Habenaria tubers are used as famine food and fed to pigs in New Guinea (Massal and Barrau 1955; Triede 1967; Powell 1976). The tubers of H. multipartita Bl. ex Kranzl. are eaten in Java (Bakhuisen van der Brink 1937), as are those of H. rumphii Lindl. in Ambon (Rumphius 1741- 1750; Smith 1927).
A decoction of the boiled tubers is widely used medicinally: an infusion of boiled tubers of H. cirrhata Rchb.f. for curing indigestion in Kenya (Kokwaro 1976); H. macrandra Lindl. as a purgative, and H. walleri Rchb.f. for stomach diseases in East Africa (Kokwaro 1976); H. ciliolaris Kranzl. for internal injuries in Sichuan, China (Cheo 1947, Hu 1971 a, b); H sp. for infected wounds in lndo-China (Dournes 1955); H. miersiana Champ. ex Benth. for dressed wounds and swellings by aboriginal people in Taiwan; and for colic in Sichuan (Cheo 1947, Liu 1952; Hu 1971 a, b). An infusion of the tubers of Habenaria species has been used in South Africa to promote fertility (Rayner 1977). Salep, used as food and an aphrodisiac or restorative in lndia and Myanmar (Burma), is produced from the tubers of H. commelinifolia and other species (Chopra et al. 1956; Kirtikar and Basu 1918; Nair 1963). (PC).
