Echinomastus
| Echinomastus | |
|---|---|
| File:Echinomastus johnsonii.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Cactoideae |
| Tribe | Cacteae |
| SubTribe | |
| Genus | Echinomastus |
| Species | |
| Notes | Taxonomy follows Joël Lodé (2015). Lodé keeps it separate from Sclerocactus, noting its conflicting phylogenetic position. |
Etymology
The name is derived from the Greek echinos (hedgehog) and mastos (breast/nipple), referring to the globose shape and the prominent tubercles of the plants.
Description
Echinomastus consists of small, usually solitary cacti, globose to shortly cylindrical in habit.
- Stems: The ribs are low and arranged in spirals, divided into tubercles that feature a characteristic groove on the upper side.
- Areoles: Often possess nectariferous glands.
- Spines: Radial spines typically cover the epidermis; central spines may be absent in some species.
- Flowers: Diurnal and self-sterile, emerging from the apex at the top of the tubercles. They lack a significant floral tube and come in colors including white, yellow, pink, and magenta.
- Fruits and Seeds: The fruits are scaly, elongated, and dehisce at the base. Seeds are black, ovate to kidney-shaped, and finely papillose.
Habitat
Echinomastus species grow in small, localized colonies within deserts or grasslands. [cite: 1003] They are found on varied substrates, frequently limestone, but also decomposed granite or volcanic lavas, at altitudes ranging from 200 m to 2400 m. [cite: 1003]
Distribution
- Mexico: Chihuahua, Coahuila, Durango, San Luis Potosí, Zacatecas. [cite: 1003]
- USA: Arizona, California, Nevada, New Mexico, Texas, Utah. [cite: 1003]
Species
Following Lodé (2015), the genus includes 8 recognized species, though he notes that several are taxonomically conflicting: [cite: 1003]
- Echinomastus durangensis
- Echinomastus erectocentrus (conflicting; possibly Sclerocactus) [cite: 1003]
- Echinomastus gautii (incertae sedis) [cite: 1002, 1003]
- Echinomastus hispidus
- Echinomastus intertextus
- Echinomastus johnsonii (conflicting; possibly Sclerocactus) [cite: 1003]
- Echinomastus mariposensis
- Echinomastus unguispinus
- Echinomastus warnockii
Taxonomy
The genus remains a subject of debate. [cite: 1003] Molecular studies (Porter et al., 2000) show a close relationship with Ancistrocactus and Sclerocactus, but only Toumeya is nested within Sclerocactus. Lodé maintains Echinomastus as a separate genus to avoid making Sclerocactus more polyphyletic.
