Autor: Backeberg

Genus honouring Walter Haage (1899-1992), German nurseryman, botanist and author specializing in cacti (see portrait above, ccourtesy of Ulrich Haage).
A genus of shrubby to treelike plants, very variable shape, prostrate, crawling, tentacular, ascending or erect. Stems cylindrical branching from the base with many low ribs (up to 26), often tuberculate, with relatively large, close-set areoles. Spines numerous (+50 in some species), sometimes covering completely the epidermis.
Flowers nocturnal, but remaining open until next morning, tubular to funnel-shaped, white, greenish-white, carmine to dull red, pollinated by bats (H. pacalaensis, H. pseudomelanostele) or by hummingbirds, also by Sphingideae for the subgenus Pygmaeocereus and observed on H. acranthus subsp. olowinskianus and H. australis (Rauh 1958, in Emerson 2007). Floral tube sturdy, scaly, hairy, setose at the base. Fruits globose to elongated, red, fleshy, having some hairs and scales, edible, floral remains persistent. Seeds numerous (up to 800), rather small, egg-shaped, black, shiny, irregularly dotted with holes, or subglobose, matt and reticulate in the subgenus Pygmaeocereus. Dispersion ensured by birds (Troglodytes aedon).
The genus Haageocereus (including Pygmaeocereus) is essentially a Peruvian genus with some species in the extreme north of Chile, and grows from sea level (taking advantage of the Pacific coastal fog, named garua in Peru, and camanchaca in Chile), on dunes of clastic sediments in the coastal desert, to the mountains west of the Andes, on sandy or rocky soils, up to 3000 m in altitude. Near the ocean, plants are very often covered with mosses and lichens (regrettably also of with plastic bags and all sort of human waste), sometimes almost completely buried in the sand.In this habitat, the surrounding vegetation is rare, very scattered and consists essentially of terrestrial Bromeliads.
Chile (Arica, Tarapaca), Peru (Ancash, Arequipa, Cajamarca, lea, La Libertad, Lambayeque, Lima, Piura, Tacna).

Currently 14 possible species, plus 8 subspecies:
– Haageocereus acranthus* (Vaupel) Backeb. 1935
– Haageocereus acranthus subsp. backebergii (Backeb.) N. Calderon 2007
– Haageocereus acranthus subsp olowinskianus* (Backeb.) Ostolaza 1998 (- H. limensis)
– Haageocereus albispinus* (Akers) Backeb. 1958
– Haageocereus (Pygm.) bieblii (Diers) J.Lode 2013
– Haageocereus (Pygm.) bieblii subsp. kuehhasii* (Diers) J.Lode 2013
– Haageocereus (Pygm.) bylesianus* (Andreae & Backeberg) J.Lode 2013
– Haageocereus decumbens* (Vaupel) Backeb. 1934 (= H. australis)
– Haageocereus (Pygm.) familiaris (Ritter) J.Lode 2013
– Haageocereus fascicularis (Meyen) Ritter 1980 (= H. chilensis (Ritter ex) Hunt 2005 nom. superfl.)
– Haageocereus lanugispinus F.Ritter 1981 (= Pygm. densiaculeatus)
– Haageocereus pacalaensis* Backeb. 1935 (= H. repens)
– Haageocereus pacalaensis subsp. repens* (Rauh & Backeb.) Ostolaza 2000
– Haageocereus platinospinus* (Werderm. & Backeb.) Backeb. 1935
– Haageocereus pseudomelanostele* (Werderm. & Backeb.) Backeb. 1935 (= H. chosicensis ?)
– Haageocereus pseudomelanostele subsp. acanthocladus (Rauh & Backeb.) Ostolaza 2003
– Haageocereus pseudomelanostele subsp. aureispinus (Rauh & Backeb.) Ostolaza 1998
– Haageocereus pseudomelanostele subsp. chryseus Hunt 2002
– Haageocereus pseudomelanostele subsp. turbidus* (Rauh & Backeb.) Ostolaza 1998
– Haageocereus pseudoversicolor* Rauh & Backeb. 1957 (= H. icosagonoides)
– Haageocereus tenuis* F.Ritter 1981
– Haageocereus versicolor* (Werderm. & Backeb.) Backeb. 1935

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