Pediocactus
| Pediocactus | |
|---|---|
| File:Pediocactus simpsonii.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Cactoideae |
| Tribe | Cacteae |
| SubTribe | |
| Genus | Pediocactus |
| Species | |
| Notes | Taxonomy follows Joël Lodé (2015). The genus is accepted as distinct from Sclerocactus. |
Etymology
The name means "plain cactus", referring to the Great Plains habitat where many species occur.
Description
Pediocactus is a genus of small, low-growing cacti adapted to cold and arid environments.
- Habit: Subglobose to short cylindrical plants, solitary or forming small clumps, with depressed apex.
- Stems: Not ribbed, but tuberculate.
- Spines: Dense, often obscuring the epidermis; radial spines sometimes pectinate; central spines straight or curved.
- Flowers: Diurnal, remaining open at night, bell-shaped; white, yellow, pink to magenta; self-sterile.
- Fruits: Globose to cylindrical, opening longitudinally or apically.
- Seeds: Obovoid to pear-shaped, papillose, dark; dispersal often by ants (myrmecochory).
Habitat
The genus grows in high deserts and plateaus, often on mineral soils such as limestone, gypsum, volcanic substrates, or gravelly plains.
Altitude range: from about 400 m up to 3300 m.
Species are adapted to harsh climates with strong temperature fluctuations and can tolerate severe frost (e.g. P. simpsonii).
Distribution
- North America:
United States (Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, South Dakota, Utah, Washington, Wyoming)
Taxonomy
The genus Pediocactus was established by Britton & Rose (1913).
It has often been associated with Sclerocactus, but molecular studies (Porter et al. 2000; Butterworth et al. 2002; Crozier 2005) demonstrate that Pediocactus is not closely related to it.
The genus is therefore maintained as distinct.
Some taxonomic confusion has occurred, particularly regarding Pediocactus sileri, which is not synonymous with Sclerocactus sileri, but represents a separate species.
According to Joël Lodé (2015), Pediocactus is a valid genus.
Species
Following the classification of Joël Lodé (2015).
- Pediocactus bradyi
- Pediocactus despainii
- Pediocactus knowltonii
- Pediocactus nigrispinus
- Pediocactus paradinei
- Pediocactus peeblesianus
- Pediocactus sileri
- Pediocactus simpsonii
- Pediocactus winkleri
Notes
- The genus is adapted to extreme climates, including freezing temperatures.
- Molecular studies have clarified its separation from Sclerocactus.
- Some taxa previously treated as subspecies are now recognized as distinct species.
