Acharagma
From M&J Cactus Wiki
| Acharagma | |
|---|---|
| File:Acharagma roseanum.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Cactoideae |
| Tribe | Cacteae |
| SubTribe | |
| Genus | Acharagma |
| Species | |
| Notes | Taxonomy follows Joël Lodé (2015) with molecular support from Wallace (1995), Butterworth et al. (2002), Crozier (2005), Hernández-Hernández et al. (2011), and Vázquez-Sánchez et al. (2013). |
Etymology
The name Acharagma means “without groove”, referring to the absence of an areolar groove on the tubercles, unlike related genera such as Coryphantha and Escobaria.
Description
Acharagma is a genus of small, globose to short cylindrical cacti with dense spination and reduced floral structures.
- Habit: Solitary or forming small clumps (caespitose).
- Roots: Fibrous to somewhat thickened.
- Stems: Globose to short cylindrical, compact.
- Ribs: Absent.
- Tubercles: Prominent, without areolar groove and without nectar glands.
- Areoles: Terminal, woolly when young.
- Spines: Numerous, dense, covering the epidermis.
- Flowers: Diurnal, apical, funnel-shaped; creamy white to yellow, often tinged pink or reddish; self-sterile.
- Pollination: By insects.
- Fruits: Naked, indehiscent; floral remnants persistent.
- Seeds: Brown to black, finely foveolate.
Habitat
Occurs in restricted semi-desert environments:
- xerophytic shrublands
- rocky slopes and hillsides
- limestone, sandstone, or gypsum substrates
- cliff crevices and mountainous terrain
Often found among shrubs or in full sun, sometimes near seasonal watercourses.
Altitude range: approximately 1000–2650 m.
Distribution
Mexico:
- Coahuila
- Nuevo León
Taxonomy
The genus is well supported as distinct and monophyletic.
Key points:
- Initially placed in Gymnocactus (Glass & Foster, 1970)
- Later transferred to Turbinicarpus and Escobaria
- Wallace (1995): molecular data indicated a distinct lineage
- Glass & Zimmerman (1998): established genus status
- Butterworth et al. (2002): separated from Escobaria
- Crozier (2005) and Hernández-Hernández et al. (2011): confirmed distinct clade
- Vázquez-Sánchez et al. (2013): confirmed monophyly
The genus is clearly separated from morphologically similar taxa.
Species
According to Joël Lodé (2015):
** Acharagma roseanum subsp. galeanense
Notes
- A highly localized genus with very restricted distribution.
- Morphologically similar to Escobaria, but lacking the diagnostic areolar groove.
- The status of Acharagma roseanum subsp. galeanense remains uncertain and may warrant species rank.
