Praecereus
From M&J Cactus Wiki
| Praecereus | |
|---|---|
| File:Praecereus euchlorus.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Cactoideae |
| Tribe | Cereeae |
| SubTribe | |
| Genus | Praecereus |
| Species | |
| Notes | Taxonomy follows Joël Lodé (2015) with additional insights from Arakaki (2008), Nyffeler & Eggli (2010), and Kiesling (2010). Placement remains uncertain (incertae sedis). |
Etymology
The name means "before Cereus", implying an ancestral or earlier lineage (prae = before).
Description
Praecereus is a genus of shrubby cacti with slender, often sprawling stems.
- Habit: Slender, cylindrical stems; erect to prostrate; strongly branched from the base.
- Stems: Without mucilage.
- Areoles: Rounded, situated on small prominences.
- Spines: Acicular, variable.
- Flowers: Nocturnal, funnel-shaped, with a curved, naked, thick-walled floral tube; white to greenish-yellow, slightly fragrant.
- Pollination: Primarily by bats (e.g. Glossophaga longirostris) and hawkmoths (Sphingidae).
- Fruits: Globose to ovoid, fleshy, red with white pulp; laterally dehiscent; floral remnants persistent.
- Seeds: Black, shiny, elongated; ruminate to tuberculate.
- Dispersal: Possibly by mammals such as tapirs (Tapirus terrestris).
Habitat
Occurs in tropical environments:
- dry forests and cerrado vegetation
- among shrubs, trees and rocks
- loamy soils, sometimes on slopes
Altitude range: sea level to approximately 2000 m.
Climate: warm year-round, with rainfall up to ~1000 mm annually.
Distribution
South America and adjacent regions:
- Argentina
- Bolivia
- Brazil
- Colombia
- Ecuador
- Paraguay
- Peru
- Trinidad
- Venezuela
Taxonomy
The genus is taxonomically problematic and considered provisionally accepted.
Key points:
- Buxbaum (1968): separated Praecereus from Cereus and Monvillea based on floral traits
- Hunt & Taylor (1986, 1990): alternated between merging and separating these genera
- Arakaki (2008): placed Praecereus euchlorus within Trichocereeae based on molecular data
- Nyffeler & Eggli (2010): highlighted non-monophyly of traditional tribes
- Kiesling (2010): suggested synonymy issues with Monvillea taxa
The genus may represent a lineage with hybrid origin or misinterpreted morphology. Its placement within Cereeae remains uncertain.
Species
Currently one species with several subspecies:
Notes
- One of the most taxonomically uncertain genera in Cactaceae.
- Morphological characters (especially floral tube structure) conflict with molecular data.
- Some taxa historically placed in Monvillea are now included here.
- Further phylogenetic studies are required to clarify its true position.
