Epiphytic herbs. Pseudobulb persistent for several years, conical, of similar length and width with one or two basal sheathing bracts, spotted with maroon or purple. Leaves deciduous after one growing season, one or two from apex of pseudobulb, petiolate, plicate, lanceolate to elliptical-lanceolate. Inflorescence produced laterally from base of pseudobulb, rachis green, pubescent, with sheathing bracts, bracts ovate-lanceolate, pale green to brownish pink or brown; floral bracts concave, ovate-lanceolate, similar in colour to rachis bracts. Sepals elliptic-lanceolate to oblanceolate, acute to obtuse, white to pink. Petals oblanceolate to spathulate, similar in colour to sepals. Labellum trilobed, lateral lobes broad, rounded, erect, white to pink with green, brown, and maroon spotting on both sides, midlobe acute, decurved apically, with three to five pink to magenta crests longitudinally. Column curved, brownish green, winged, pubescent; anther trilobed, pollinia eight. Ovary pubescent. (DG).
Ancistrochilus comprises only two species. Ancistrochilus rothschildianus O’Brien ranges through Central Africa from Guinea, Liberia, and Sierra Leone east to Benin, Cameroon, Central African Republic, Equatorial Guinea, Gabon, Ivory Coast, southern Nigeria, Uganda, and northern Zaire. Ancistrochilus thomsonianus is restricted to Cameroon, Nigeria, and Zaire (Christenson 2002). (DG).
Cribb (1979) and Stewart and Hennessey (1981) stated that Ancistrochilus is epiphytic in shade on rain forest trees in regions with a minimal dry season. The two species are known from up to 1200 m above sea level (Cribb 1979; Christenson 2002), flowering from September to December (Stewart and Hennessey 1981). Goh et al. (1982) mentioned that flowering in A. rothschildianus is probably induced by short day-length. (DG).
Both species are occasionally seen in the horticultural trade. (DG).
Cribb (1979) suggested mounting plants of this genus on bark or growing them in pots with bark chips with moderate shade and high humidity during growth and a minimum night temperature of 15 ͦ C. Once growth is completed and leaves have fallen, watering should be reduced. Sheehan and Sheehan (1994) recommended cultivation in any basic epiphytic medium, a minimum night temperature of 15 ͦ C, monthly fertilization with a balanced fertilizer, and reduced watering following flowering. Bertaux (1994) suggested a well-draining medium of pine bark, polystyrene, and clay chips, with frequent fertilization until dormant. Neptune (2000) grew plants in bright light in a shallow container of bark chips, fertilized frequently, and provided a dry period of one month after flowering. Christenson (2002) recommended a well-draining terrestrial medium, providing moderate light levels and intermediate temperatures, heavy watering while in active growth, and annual repotting. Horticultural discussions have also been published by Klaasen (2002), Mannens (2002), and van Hummel (2002). Ancistrochilus rothschildianus grows well in partial shade in a container of living Sphagnum moss that is always moist (watered with distilled water to preserve the moss). Following fertilization, flushing the moss with distilled water and rapid drainage are necessary to remove fertilizer salts that will kill the moss (Goldman, personal observations). (DG).
There is no published information on the pollination of Ancistrochilus. (DG).
Ancistrochilus originally was considered to be part of the Asian genus Pachystoma (Reichenbach 1879), but Pfitzer (1889) placed the species in Ipsea. Rolfe (1897) determined that Ancistrochilus was similar to Pachystoma based on its free perianth parts and pollinia attached to a single stipe. The taxonomic history of this genus was summarized by Cribb (1979) and Christenson (2002). Van den Berg et al. (2005) placed Ancistrochilus in Collabiinae. (DG).