Cereus
| Cereus | |
|---|---|
| File:Cereus hildmannianus.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Cactoideae |
| Tribe | Cereeae |
| SubTribe | Cereinae |
| Genus | Cereus |
| Species | |
| 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 (except in C. mortensenii, which produces a 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 diverse: night-blooming species are visited by hawkmoths (Sphingidae) and bats, while flowers remaining open in the morning attract hummingbirds. The fruits are fleshy, globose to ovoid, and exhibit lateral dehiscence (splitting on the side). They come in various colors—green, red, yellow, or blue—and contain large, black, tuberculate seeds. Interestingly, animals like the tapir (Tapirus terrestris) play a role in seed dispersal in certain regions.
Habitat
The genus is incredibly adaptable, growing from sea level up to 3200 m in altitude. They are found in thorny thickets, dry forests, and on 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, and various Caribbean Islands.
Species
Joël Lodé recognizes 26 species (some with subspecies). Notable members include:
- Cereus aethiops
- Cereus fernambucensis
- Cereus hexagonus
- Cereus hildmannianus
- Cereus jamacaru (Mandacaru)
- Cereus repandus (Peruvian Apple Cactus)
- Cereus validus
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.
