Tephrocactus
| Tephrocactus | |
|---|---|
| File:Tephrocactus articulatus.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Opuntioideae |
| Tribe | Tephrocacteae |
| SubTribe | |
| Genus | Tephrocactus |
| Species | |
| Notes | Taxonomy follows Joël Lodé (2015). The genus is accepted in an expanded sense. |
Etymology
The name means "ash cactus", referring to the ash-grey epidermis typical of some species.
Description
Tephrocactus is a genus of small, bushy to shrubby cacti composed of articulated segments.
- Habit: Low, branching plants with terminal or subterminal branching.
- Stems: Composed of globose or cylindrical segments, often appearing stacked in chains; segments easily detach.
- Roots: Sometimes tuberous.
- Leaves: Tiny, deciduous.
- Areoles: With trichomes; glochids sunken in cavities with small openings.
- Spines: Variable, sometimes absent.
- Flowers: Diurnal, rotate, white, pink, yellow, orange or red; self-sterile.
- Fruits: Dry or fleshy, dehiscent when ripe.
- Seeds: Large, irregular, light-coloured; embryo comma-shaped; dispersal by wind or animals (endozoochory).
Habitat
The genus occurs in arid to semi-arid regions, on rocky slopes, plains and puna grasslands, often in full sun.
Altitude range: from about 250 m up to 3800 m.
Distribution
- South America:
Argentina (wide distribution), Bolivia (Potosí, Chuquisaca), Chile (Tarapacá)
Taxonomy
The genus Tephrocactus was established by Lemaire (1868).
Recent molecular studies (Griffith & Porter 2009; Nyffeler & Eggli 2010; Ritz et al. 2012) have clarified its circumscription.
Several taxa formerly included in Puna have been reassigned:
- Puna bonnieae → Tephrocactus bonnieae
- Puna clavarioides → Maihueniopsis
- Puna subterranea → Cumulopuntia
Some species such as T. nigrispinus and T. verschaffeitii show atypical features and complicate morphological definitions.
The genus is characterized by acrotonic branching and glochids sunken in cavities.
According to Joël Lodé (2015), Tephrocactus in an expanded sense is a valid genus.
Species
Following the classification of Joël Lodé (2015).
- Tephrocactus alexanderi
- Tephrocactus aoracanthus
- Tephrocactus articulatus
- Tephrocactus bonnieae
- Tephrocactus geometricus
- Tephrocactus molinensis
- Tephrocactus nigrispinus
- Tephrocactus recurvatus
- Tephrocactus verschaffeitii
- Tephrocactus weberi
Notes
- The genus includes species with diverse morphology, especially in seed structure.
- Some taxa previously placed in other genera have been reassigned based on molecular data.
- Seed dispersal occurs both by wind and animals (e.g. rodents and camelids).
- Certain species form distinct clades within the genus.
