View source for Cereus

{{Taxobox
| name = Cereus
| image = Cereus_hildmannianus.jpg
| kingdom = [[Plantae]]
| family = [[Cactaceae]]
| subfamily = [[Cactoideae]]
| tribe = [[Cereeae]]
| subtribe = [[Cereinae]]
| genus = '''Cereus'''
| notes = Taxonomy follows Joël Lodé (2015).
}}

== Etymology ==
The name stems from the Latin word ''cereus'', meaning "wax candle," referring to the straight, cylindrical, candle-like growth habit of the stems.

== Description ==
'''Cereus''' is a genus of shrubby or treelike cacti, often reaching massive proportions with well-defined trunks. The stems are angular and strongly ribbed, featuring large, woolly areoles that typically lack long hairs. A unique exception is ''Cereus mortensenii'', which is the only species in the genus to produce a dense, woolly pseudocephalium. The spines are usually sturdy and needle-like (aciculate).

The flowers are nocturnal, large, and funnel-shaped. They are mostly white, but can be yellowish or tinted with purple. Pollination is a nocturnal affair: night-blooming species are visited by hawkmoths (Sphingidae) and bats (such as ''Glossophaga'' and ''Leptonycteris''). Flowers remaining open in the morning also attract hummingbirds like ''Chlorostilbon aureiventris''. 

The fruits are globose to ovoid, fleshy, and exhibit lateral dehiscence (splitting on the side). They are highly variable in color—greenish, yellow, red, or bluish. They contain large, black, tuberculate seeds. In their natural habitat, animals like the tapir (''Tapirus terrestris'') are known to assist in seed dispersal.

== Habitat ==
The genus is incredibly adaptable, growing from sea level up to 3200 m in altitude. They are found in diverse environments across South America, including thorny thickets, dry forests, and rocky volcanic slopes. They can thrive both in deep shade and in full equatorial sun.

== Distribution ==
A wide-ranging genus across South America and the Caribbean:
* '''Argentina, Bolivia, Brazil, Colombia, Ecuador, Paraguay, Peru, Uruguay, Venezuela, Guyana, French Guyana, and the Caribbean Islands (Grenada, Trinidad & Tobago).'''

== Species ==
According to the Joël Lodé index, the genus includes 26 recognized species and several subspecies:

* [[Cereus aethiops]]
* [[Cereus albicaulis]]
* [[Cereus bicolor]]
* [[Cereus braunii]]
* [[Cereus cochabambensis]]
* [[Cereus colosseus]]
* [[Cereus comarapanus]]
* [[Cereus fernambucensis]]
** [[Cereus fernambucensis subsp. sericifer]]
* [[Cereus fricii]]
* [[Cereus grenadensis]]
* [[Cereus hankeanus]]
* [[Cereus hexagonus]]
* [[Cereus hildmannianus]]
** [[Cereus hildmannianus subsp. uruguayanus]]
* [[Cereus horrispinus]]
* [[Cereus huilunchu]]
* [[Cereus insularis]]
* [[Cereus jamacaru]]
** [[Cereus jamacaru subsp. calcirupicola]]
* [[Cereus lanosus]]
* [[Cereus mirabella]]
* [[Cereus mortensenii]]
* [[Cereus pierre-braunianus]]
* [[Cereus repandus]]
* [[Cereus stenogonus]]
* [[Cereus trigonodendron]]
* [[Cereus validus]]
* [[Cereus vargasianus]]

== Notes ==
* Modern molecular studies (Machado et al. 2006, Nyffeler 2010) show that ''Cereus'' as currently defined is polyphyletic, meaning it will likely be split or reorganized in the future.
* Joël Lodé maintains ''Monvillea'' as a separate genus, refusing to include it as a subgenus (Ebneria) within ''Cereus''.
* ''Cereus mortensenii'' is a taxonomic outlier due to its pseudocephalium; Lodé suggests it may be a natural hybrid between ''Cereus'' and ''Melocactus''.
* The genus ''Piptanthocereus'' is no longer recognized and its species are moved here.

[[Category:Cactaceae]]
[[Category:Cactoideae]]
[[Category:Cereeae]]
[[Category:Cereinae]]