Origin and Habitat: Veracruz and Oaxaca, Mexico.
Habitat: It is a rain-forest species that grows on trees as an epiphyte (or occasionally on rocks as a lithophytic plant). In other words, these are cacti that grow in trees! They grow their roots into the bark of their host tree. Their only access to moisture and nutrients is from rain and droppings that fall from above. They also always grow under a canopy of trees and are never exposed to the full sun of the desert.

• Disocactus ackermannii (Haw.) Ralf Bauer
• Cactus ackermannii (Haw.) Lindl.
• Cereus ackermannii (Haw.) Pfeiff.
• Epiphyllum ackermannii Haw.
• Epiphyllum cruentum hort.
• Heliocereus ackermannii (Lindl.) Doweld
• Nopalxochia ackermannii (Haw.) F.M.Knuth in Backeb. & F.M.Knuth
• Phyllocactus ackermannii (Haw.) Salm-Dyck

• Disocactus ackermannii (Haw.) Ralf Bauer
• Cactus ackermannii (Haw.) Lindl.
• Cereus ackermannii (Haw.) Pfeiff.
• Epiphyllum ackermannii Haw.
• Epiphyllum cruentum hort.
• Heliocereus ackermannii (Lindl.) Doweld
• Nopalxochia ackermannii (Haw.) F.M.Knuth in Backeb. & F.M.Knuth
• Phyllocactus ackermannii (Haw.) Salm-Dyck
• Disocactus ackermannii f. candidus (Alexander) Barthlott
• Epiphyllum ackermannii f. candidum Alexander
• Nopalxochia ackermannii f. candida (Alexander) Alexander

• Disocactus ackermannii subs. conzattianus (T.MacDoug.) U.Guzmán
• Disocactus ackermannii var. conzattianus (T.MacDoug.) Barthlott
• Heliocereus conzattianus (T.MacDoug.) Doweld
• Nopalxochia ackermannii var. conzattiana (T.MacDoug.) Kimnach
• Nopalxochia conzattiana T.MacDoug.
• Pseudonopalxochia conzattiana (T.MacDoug.) Backeb.

Description: It is a very delightful epiphytic perennial cactus, that forms clumps about 30 cm high with a 60-100 cm spread. It’s a heavy bloomer and easily flowered plant that has the very appropriate and descriptive popular name, the “Red Orchid Cactus” For many years this species has aroused much controversy among horticulturists and botanists alike and it was assigned to the genus Epiphyllum by Haworth in 1829 but later some botanists considered it to be a natural hybrid between DisoSN'>8517' alt='8518'>Cactus phyllanthoides#SN#8518'>Diso[[Cactus phyllanthoidesSN' style='border:none;'> and Heliocereus speciosusSN|7266]]SN|7266]]. This is one of the original varieties from which many hybrids have been made.
Stems: Branching basally, somewhat leaflike, fleshy, elongated, flattened, erect, becoming pendant about 20-40 cm long ( mostly less than 30 cm long, but sometimes up to 1 m long) with prominent middle and side veins, margin crenate ('having the edge notched'), stem bases round in cross section and 10-18 cm long, flattened portions 10-75 cm long, 5-7 cm wide, brownish when young becoming dark green.
Spines: Unarmed, with only short bristles on younger and lower portions.
Flowers: Large, curved, funnelform and showy up to 11-14 cm across, deep-crimson with greenish throats, Stigma red or purplish with no white lobes.
Blooming season: Spring, the flowers tend to open in the afternoon or evening and remain opened both night and day for several days (usually 3). Species that are put in the Epiphyllum genus today are all night bloomers.
Fruits: ovoid to oblong, green to brownish red, 4 cm long, 2-2,5 cm in diameter.

Cultivation and Propagation: This plants are vigorous growers that appreciate more organic matter in potting mixes than most terrestrial cacti and do best in soils containing sphagnum. This type of soil would normally be used for orchids, bromeliads or other epiphytic plants. They require ample summer water and partial shade, but allow soil to dry slightly between waterings; During the flowering cycle keep them moist (but not soggy). After the blossoms have fallen off you should back off on the water for a couple of months. If they need repotting, this is the time to do it. They drop their buds easily if they are moved. Once flower buds have formed, DO NOT MOVE the plant, as slight changes in environment may cause the buds to drop. These forest cacti tend to be long lived.
Growing tips: It can be trained on a support, allowed to grow pendant, or grafted onto a straight stem of some other species to produce a beautiful small weeping tree. Older branches over two years old, which become brown and unsightly, can be cut away to the ground without disfiguring the plant.
Propagation: Stem cuttings, Grafting (For grafting this plant Acanthocereus pentagonusSN|4326]]SN|4326]] is a good stock)