Microcoelia Lindl., Gen. Sp. Orchid. Pl.: 60 (1830).
Synonyms:
Microcaelia Hochst. ex A.Rich., Tent. Fl. Abyss. 2: 285 (1850).
Dicranotaenia Finet, Bull. Soc. Bot. France 54(9): 47 (1907).
Rhaphidorhynchus Finet, Bull. Soc. Bot. France 54(9): 32 (1907).
Encheiridion Summerh., Bot. Mus. Leafl. 11: 161 (1943).
Description:
Epiphytic aphyllous herbs, rarely epilithic. Stems usually unbranched, bearing numerous scale leaves and roots, the living part short but sometimes with an elongated dead part at the base. Scale leaves acute to rostrate, protecting the stem apex. Roots firmly or loosely attached to substrate, branched or unbranched, smooth or verrucose, terete or flattened. Inflorescences axillary, racemose, few- to many-flowered. Flowers resupinate, small, usually white but sometimes tinged with pink, brown or green. Sepals and petals free, mostly erect or spreading; lip free, almost entire to rather obscurely three-lobed, spurred at the base. Column very short to elongate, androclinium excavated, anther terminal; rostellum lobes 2, short to very long, dependent to porrect; pollinia 2, sessile on single stipes; viscidium 1, variously shaped; stigma distinctly excavated below the rostellum, variously shaped. Ovary short or elongated. Capsule cylindrical, ellipsoid or ± globose, sessile or pedicellate.
Cultivation:
Species of Microcoelia are not common in cultivation, but they deserve to be grown much more frequently. Although the flowers are small, they are often densely packed together and many have a glistening texture. Because they photosynthesize through their roots, they must be mounted, rather than having the roots buried in compost. They seem to prefer smooth pieces of wood instead of the usual slabs of cork or pine bark; reshwater driftwood, or bogwood seems to be ideal. Sea driftwood could be used, but it would need to be soaked for some time to get rid of the salt. Microcoelia can also grown on branches of smooth-barked trees, such as silver birch. Plants can some-times take a while to become established, but once they decide to grow, they do so well. Most species seem to do well in intermediate temperatures, in moderate to light shade. Humidity must be high, especially when the plants are growing actively, and plants should not be allowed to dry out too much.
Notes:
The genus Microcoelia was established by John Lindley in 1830. The name is derived from the Greek words mikros (small) and koilia (abdomen), referring to the globose spur of M. exilis, the type species of the genus. The genus was revised by V. S. Summerhayes in 1943; he removed some leafless species to other genera, leaving 25 species in Microcoelia. The most recent revision is by Lars Jonsson in 1981; he. recognized 26 species in Africa and Madagascar; one more African species, M. ornithocephala, has been described since then by P. J. Cribb in 1985.
Distribution:
Trop. & S. Africa, Comoros, Madagascar
Species:

World Checklist of Selected Plant Families.). The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 31/10/2020
Bibliography and References:
Arends JC, Van der Laan FM. 1986 Cytotaxonomy of the Vandeae. Lindleyana. 1. 33-41.
Carlsward BS, Stern WL, Bytebier B. 2006 Comparative vegetative anatomy and systematics of the angraecoids (Vandeae, Orchidaceae)
with an emphasis on the leafless habit. Bot. J. Linn. Soc. 151. 165-218.
Fibeck W, Phiri V. 1998 Leafless orchids in Zimbabwe. S. Afr. Orchid J. 29. (3): 79-82 (1998)
Jonsson L. 1981 A monograph of the genus Microcoelia (Orchidaceae). vol. 23 : Symb. Bot. Upsal., 151p. (1981)
La Croix I. 2004 Microcoelia, African jewels. Orchid Dig. 68. (2): 79-85 (2004)
La Croix T. 2006 Microcoelia in Malawi. Orchid Rev. 114. (1271): 266-270. Geog = 5 Col. illus. (KR, 200701578).
Pottinger M. 1982 African orchids: genera from 'G" to 'M'. Orchid Rev.,90 (1068): 327-329 (1982)
Stewart J. 1973 African orchids: more about Microcoelias. Amer. Orchid Soc. Bull. 42. (9): 801-805 (1973)
Teuscher H. 1972 Microcoelia guyoniana and other leafless epiphytic Orchids. Amer. Orchid Soc. Bull. 41. (6): 497-501 (1972)