Autor: Lindley

“Double Cactus” because the inner and outer segments of the flowers of this genus have an equal length.
A genus of epiphytic or lithophytic plants, ribbed or flattened stems (phylloclades). Spines setose or absent, areoles often numerous.
Flowers usually diurnal, self-sterile and pollinated by hummingbirds (except D. macranthus?), rather large, of different size and shape, funnel-shaped or tubular, sometimes zygomorphic, rarely rotate, white, pink to red or pink purple. Stamens arranged in two series. Fruits like berries, almost naked or weakly scaly. Seeds ovate, covered by an envelope of mucilage, shiny or matt, brown to black.
The genus Disocactus grows epiphytically in the tropical cloud forests of southern Mexico and Central America, from approximately 700 m up to 2100 m in altitude.
El Salvador, Guatemala (Baja Verapaz, Chimaltenango, Escuintla, Huehuetenango, Quetzaltenango, Quiche, Sacatepequez, San Marcos, Santa Rosa, Solola), Honduras (Comayagua), Mexico (Chiapas, Colima, Durango, Guerrero, Jalisco, Mexico D.F., Michoacan, Morelos, Nayarit, Oaxaca, Sinaloa, Veracruz), Nicaragua (Jinotega).

Currently 8 species to debate:
– Disocactus ackermannii* (Haw.) Barthlott 1991
– Disocactus biformis* (Lindi.) Lindi. 1845
– Disocactus eichlamii (Weing.) Britton & Rose 1913
– Disocactus macdougallii (Alexander) Barthlott 1991
– Disocactus macranthus (Alexander) Kimnach & Hutchison 1957
– Disocactus nelsonii (Britton & Rose) Lindinger 1942 (non Selenicereus nelsonii)
– Disocactus phyllanthoides (DC.) Barthlott 1991
– Disocactus quetzaltecus (Standi. & Steyerm.) Kimnach 1959

References: "TAXONOMY of the CACTACEAE" -  ISBN 978-84-617-3723-9 (Vol. 1)