AFRICAN

ORCHIDS

Habenaria Willd. Sp. Pl. 4: 44 (1805).
Homotypic Names:
Habenorkis Thouars, Nouv. Bull. Sci. Soc. Philom. Paris 1: 317 (1809), nom. superfl.
Heterotypic Synonyms:
Mesicera Raf., Neogenyton: 4 (1825).
Aopla Lindl., Edwards's Bot. Reg. 20: t. 1701 (1834).
Bilabrella Lindl., Edwards's Bot. Reg. 20: t. 1701 (1834).
Ate Lindl., Gen. Sp. Orchid. Pl.: 326 (1835).
Diplectraden Raf., Fl. Tellur. 2: 90 (1837).
Nemuranthes Raf., Fl. Tellur. 2: 61 (1837).
Synmeria Nimmo in J.Graham, Cat. Pl. Bombay, Add.: s.p. (1839).
Centrochilus Schauer, Nov. Actorum Acad. Caes. Leop.-Carol. Nat. Cur. 19(Suppl. 1): 435 (1843).
Dissorhynchium Schauer, Nov. Actorum Acad. Caes. Leop.-Carol. Nat. Cur. 19(Suppl. 1): 434 (1843).
Macrocentrum Phil., Anales Univ. Chile 36: 200 (1870).
Montolivaea Rchb.f., Otia Bot. Hamburg.: 107 (1881).
Podandria Rolfe in D.Oliver & auct. suc. (eds.), Fl. Trop. Afr. 7: 205 (1898), nom. illeg.
Habenella Small, Fl. S.E. U.S.: 316 (1903).
Itaculumia Hoehne, Bol. Mus. Nac. Rio de Janeiro 12(3-4): 79 (1936).
Kryptostoma (Summerh.) Geerinck, Bull. Jard. Bot. Natl. Belg. 52: 149 (1982).
Ala Szlach., Fragm. Florist. Geobot., Suppl. 3: 113 (1995), contrary to Art. 20.2 ICBN (1994).
Podandriella Szlach., Fl. Cameroun 34: 194 (1998).
Pseudoperistylus (P.F.Hunt) Szlach. & Olszewski, Fl. Cameroun 34: 210 (1998).
Renzorchis Szlach. & Olszewski, Adansonia, sér. 3, 20: 324 (1998).
Alinorchis Szlach., Polish Bot. J. 46: 129 (2001).
Senghasiella Szlach., J. Orchideenfr. 8: 365 (2001).
Arachnaria Szlach., Richardiana 3: 153 (2003).
Ceratopetalorchis Szlach., Górniak & Tukallo, Richardiana 3: 158 (2003).
Macrura (Kraenzl.) Szlach. & Sawicka, Orchidee (Hamburg) 54: 331 (2003).
Mirandorchis Szlach. & Kras-Lap., Orchidee (Hamburg) 54: 84 (2003).
Pseudocoeloglossum (Szlach. & Olszewski) Szlach., Orchidee (Hamburg) 54: 334 (2003).
Pseudohemipilia Szlach., Orchidee (Hamburg) 54: 214 (2003).
Schlechterorchis Szlach., Orchidee (Hamburg) 54: 217 (2003).
Trachypetalum Szlach. & Sawicka, Orchidee (Hamburg) 54: 88 (2003).
Bertauxia Szlach., Richardiana 4: 56 (2004).
Fimbrorchis Szlach., Orchidee (Hamburg) 55: 489 (2004).
Kraenzlinorchis Szlach., Orchidee (Hamburg) 55: 57 (2004).
Kusibabella Szlach., Richardiana 4: 58 (2004).
Medusorchis Szlach., Orchidee (Hamburg) 55: 487 (2004).
Ochyrorchis Szlach., Richardiana 4: 52 (2004).
Plantaginorchis Szlach., Richardiana 4: 61 (2004).
Platantheroides Szlach., Richardiana 4: 103 (2004).
Smithanthe Szlach. & Marg., Orchidee (Hamburg) 55: 172 (2004).
Platycorynoides Szlach., Orchidee (Hamburg) 56: 205 (2005).
Odisha S.Misra, Orchids India: 251 (2007).
Rhinorchis Szlach., Richardiana 13: 73 (2012).
Plectoglossa (Hook.f.) K.Prasad & Venu, Rheedea 25: 88 (2015).
Description:
Terrestrial, or rarely epiphytic, herbs with elongated fleshy or tuberous roots. Stems unbranched, sometimes very short. Leaves variously arranged along the stem, sometimes 1 or 2 radical and adpressed closely to the ground, the cauline ones sometimes sheath-like. Inflorescence terminal, 1-many-flowered. Flowers usually resupinate, but in a few species not so, usually white and/or green, rarely yellow, orange or pink. Sepals usually free, the laterals spreading, the dorsal often forming a helm with the 2 petals. Petals often adherent to the dorsal sepal, entire or variously divided, often 2-lobed nearly to the base. Lip usually slightly adnate at the base to the column, the free part entire or variously divided or lobed, spurred at the base; spur short, sac-like to long and slender. Column tall or short, slender or thickened; anther upright or reclinate, the loculi adjacent and parallel with a narrow connective, or separated from one another by a much broadened filament and divergent, canals short or much elongated, adnate to the lateral lobes of the rostellum, auricles (staminodes) sometimes elongated or 2-lobed, usually rugose; pollinaria 2, each with sectile pollinium, short or elongated caudicle and rather small naked viscidium; stigmatic processes distinct, shortly club-shaped to very long with capitate or club-shaped apices, usually free, but sometimes united in the lower part to the rostellum, the rostellum side lobes divergent, short or long, middle lobe tall and overtopping the anther to short and very blunt or scarcely developed. Capsules oblong or fusiform.
The genus Habenaria was established by Carl Ludwig von Willdenow in 1805. The name derives from the Latin habena (reins), presumably referring to the straplike petal and lip lobes, and long, slender spur, found in many species. It is one of the largest terrestrial genera, with about 600 species found in tropical, subtropical, and warm temperate areas around the world. About 200 species occur in tropical and South Africa, with the greatest number in central and southern central Africa.
Terrestrial orchids with green flowers nearly all belong to the genus Habenaria, or to its close relatives Roeperocharis and Bonatea. A few species of Habenaria have white flowers. There are also many that have green sepals while some or all of the other parts of the flower are white. All have rather narrow perianth parts, particularly the hip that is often divided into three lobes. The petals are also lobed in many of the species, with an upper lobe that adheres to the edge of the dorsal sepal and a lower lobe that hangs downwards in front of the lateral sepals or parallel with the side lobes of the hip.
The plants are also rather easily recognized, even when not in flower, by their densely leafy stems, or by two large basal leaves, fiat on the ground and sheath-covered stems. In those species with many leaves, there are often a few sheaths at the base, then a group of large leaves, and the upper part of the stem is clothed with small leaves or sheaths that gradually intergrade into the bracts.
Habitat:
Many of the grassland habitats have been so changed, either by grazing, draining or conversion to agriculture, that the places where these orchids used to grow have largely disappeared. Some of the highland and coastal habitats remain and are protected, and some rather spectacular species can be found in these areas by searching at the right time of year.
Cultivation:
Plants should be grown in a standard terrestrial mix. As with almost all terrestrial orchids, good drainage is essential. When species die back after flowering, they should be kept virtually dry during their resting period, although a light sprinkling of water can be given, perhaps once a month, to prevent shrivelling of the tubers. This is roe time to repot; old dead roots can be pulled away, but it is not necessary to repot every year, as long as roe compost is still open. When new shoots start to appear, careful watering can start, although it is best to wait until the shoots are 2.5 cm tall. Once the plant is growing strongly, water can be given more freely, although the compost should never be allowed to become soggy. In common with most terrestrial orchids, it is best to avoid getting water on the leaves. Very few of the species of Habenaria are in cultivation.
Notes:
Habenaria has been the study of a monographic survey by Kraenzlin many years ago (Orch. Gen. et Sp. 1: 174-469 (1897-98)). Since this work appeared, the large number of new species described, especially from Africa, has rendered Kraenzlin’s classificatory treatment inadequate. A new revision, on a world basis, is needed to ascertain sectional limits and to bring their nomenclature up to date. It is highly probable that some of the sectional names used for African Habenarias are pre-dated by some from other areas, but nevertheless the following conspectus is offered until such time as a full treatment appears. So I have made a key from five different areas, see below.
Key to the genus Habenaria in Tropical East Africa - Key to the genus Habenaria artificial groups in Flora Zambesiaca regionen
Overview to the genus Habenaria from Reunion, Madagascar and Comoros Key to the genus Habenaria in South Africa - Overview of the Habenaria species which does not fit in the above keys.
Bibliography and References:
The International Plant Names Index (2020). Published on the Internet http://www.ipni.org [accessed 13.04.2020