Espostoa
From M&J Cactus Wiki
| Espostoa | |
|---|---|
| File:Espostoa lanata.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Cactoideae |
| Tribe | Cereeae |
| SubTribe | Trichocereinae |
| Genus | Espostoa |
| Species | |
| Notes | Taxonomy follows Joël Lodé (2015) with additional insights from Arakaki (2003, 2008), Nyffeler & Eggli (2010), and Lendel et al. (2006). |
Etymology
Named in honour of Nicolas Esposto (1877–?), Peruvian botanist of Italian origin and founder of the National School of Agriculture of La Molina, Lima.
Description
Espostoa is a genus of columnar, often densely hairy cacti, forming shrubs or tree-like structures.
- Habit: Bushy or arborescent; branching from the base or higher up.
- Stems: Columnar with numerous ribs.
- Spines: Sturdy or hair-like; often obscured by dense wool.
- Cephalium: Lateral, developing on mature stems; densely woolly.
- Flowers: Nocturnal, tubular to campanulate, white to creamy-yellow; often with an unpleasant odour.
- Floral tube: Short, scaly, without spines.
- Pollination: Primarily by bats (e.g. Anoura geoffroyi, Glossophaga soricina), also by bees and hummingbirds in some species.
- Fruits: Globose to ovoid, fleshy, sometimes with tufts of hairs; floral remnants persistent.
- Seeds: Black, shiny, finely pitted; variable between species.
Habitat
Occurs in varied environments along the western Andes:
- rocky coastal valleys and canyons
- mountain slopes and hills
- dry woodlands to more humid forest margins
Altitude range: approximately 450–2800 m or higher.
Often grows among bromeliads and low vegetation, sometimes forming dense populations.
Distribution
Western South America:
- Ecuador (Azuay, El Oro, Loja)
- Peru (Amazonas, Ancash, Cajamarca, Ica, La Libertad, Lambayeque, Lima, Piura)
Taxonomy
The genus is accepted but has undergone revisions.
Key points:
- Originally described with a single species (E. lanata)
- Thrixanthocereus has often been included but is treated separately here
- Nyffeler & Eggli (2010): reinstated Vatricania as a distinct genus, excluding it from Espostoa
- Arakaki (2008): showed close relationship with Haageocereus (sister genera)
The genus is considered monophyletic in a restricted sense (s.s.).
Species
Following Joël Lodé (2015):
Notes
- Known for dense woolly covering — an adaptation to intense sun and arid conditions.
- Lateral cephalium is a defining characteristic.
- Some taxa were historically confused or misidentified (e.g. E. utcubambensis).
- Hybridisation with related genera (e.g. Haageocereus) may occur in habitat.
