Cephalocereus
| Cephalocereus | |
|---|---|
| File:Cephalocereus senilis.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Cactoideae |
| Tribe | Phyllocacteae |
| SubTribe | Echinocereinae |
| Genus | Cephalocereus |
| Species | |
| Notes | Taxonomy follows Joël Lodé (2015). |
Etymology
The name Cephalocereus means "Head candle" (from Greek kephale, head, and Latin cereus, wax candle), referring to the woolly pseudocephalium near the top of the stems which resembles a head.
Description
Cephalocereus is a genus of large, columnar, treelike cacti that are usually solitary or branch sparingly from the base. A defining feature of many species is the presence of long, hair-like bristles or "wool" that can sometimes entirely cover the epidermis, protecting the plant from intense sun.
The flowers are nocturnal and emerge from a specialized flowering zone called a pseudocephalium. They are tubular to bell-shaped, ranging in color from white-pinkish to pale yellow, and are primarily pollinated by bats. The fruits are ovoid, covered with small scales and wool, containing shiny black, pear-shaped (pyriform) seeds.
Habitat
Endemic to Mexico, these cacti often grow in large colonies that dominate the landscape. They are found in ravines and on steep rocky slopes at altitudes between 1000 m and 1850 m. Depending on the species, they grow on diverse geological substrates including limestone, quartz, sandstone, and even volcanic andesite.
Distribution
- Mexico (Chiapas, Guanajuato, Hidalgo, Oaxaca, Puebla, Veracruz)
Species
Currently, Joël Lodé recognizes five species (including some previously placed in Haseltonia and Neodawsonia):
- Cephalocereus apicicephalium
- Cephalocereus columna-trajani
- Cephalocereus nizandensis
- Cephalocereus senilis (The "Old Man Cactus")
- Cephalocereus totolapensis (Note: sometimes considered invalid due to lack of type designation)
Notes
- The classification of Cephalocereus is still a subject of debate among taxonomists. Recent molecular studies (Arias et al., 2003; Hernández-Hernández et al., 2011) suggest that the genus may eventually be expanded to include Neobuxbaumia to ensure it is a monophyletic group.
- The genus currently includes taxa formerly described under Haseltonia and Neodawsonia.
- While Joël Lodé places it in the tribe Phyllocacteae (subtribe Echinocereinae), historical classifications often placed it in Pachycereeae.
