Astrophytum: Difference between revisions

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Created page with "{{Taxobox | name = Astrophytum | image = Astrophytum_myriostigma.jpg | kingdom = Plantae | family = Cactaceae | subfamily = Cactoideae | tribe = Cacteae | genus = '''Astrophytum''' | notes = Taxonomy follows Joël Lodé (2015). }} == Etymology == The name Astrophytum means "Star plant", referring to the typical star-like shape of several species within the genus. == Description == '''Astrophytum''' is a genus of usually solitary and highly variable plan..."
 
 
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| tribe = [[Cacteae]]
| tribe = [[Cacteae]]
| genus = '''Astrophytum'''
| genus = '''Astrophytum'''
| notes = Taxonomy follows Joël Lodé (2015).
| authority = Lemaire (1839)
| notes = Taxonomy follows Joël Lodé (2015) with molecular support from Cota & Wallace (1996), Bárcenas et al. (2011), Hernández-Hernández et al. (2011), and Vázquez-Sánchez et al. (2013).
}}
}}


== Etymology ==
== Etymology ==
The name Astrophytum means "Star plant", referring to the typical star-like shape of several species within the genus.
The name ''Astrophytum'' means “star plant”, referring to the star-shaped form of several species.


== Description ==
== Description ==
'''Astrophytum''' is a genus of usually solitary and highly variable plants. Their forms range from flattened and globose to elongated or shortly columnar. A distinctive feature of most species is the presence of flaky white scales (trichomes) covering the epidermis, though some have spiny scales. The stems have well-defined ribs, except for ''A. caput-medusae'', which possesses very elongated tubercles. Spines may be present or absent depending on the species.
'''Astrophytum''' is a genus of usually solitary cacti with distinctive ribbed or tuberculate bodies and characteristic epidermal trichomes.


The flowers are diurnal, self-sterile, and emerge apically. They are funnel-shaped and typically yellow, though some species feature a red or orange centre. Pollination is primarily carried out by bees. The fruits are globose, covered with persistent scales, and become dehiscent (split open) when ripe. The seeds are brown, light, and helmet-shaped. Seed dispersal occurs through hydrochory (water) or myrmecochory (ants).
* '''Habit''': Solitary; rarely clustering; globose, flattened or short columnar.
* '''Roots''': Thickened, adapted to arid conditions.
* '''Stems''': Green to grey-green, often densely covered with white flaky scales (trichomes).
* '''Ribs''': Well defined (typically 3–8), or replaced by elongated tubercles in some species.
* '''Tubercles''': Present only in ''A. caput-medusae'', elongated and irregular.
* '''Areoles''': Small, often woolly; sometimes bearing spines.
* '''Spines''': Present or absent depending on species.
* '''Flowers''': Diurnal, apical, funnel-shaped; yellow, often with red or orange centre; self-sterile.
* '''Pollination''': By bees.
* '''Fruits''': Globose, scaly; dehiscent at maturity.
* '''Seeds''': Brown, helmet-shaped; relatively light.
* '''Dispersal''': By water (hydrochory) or ants (myrmecochory).


The genus is divided into three sub-genera:
== Habitat ==
* '''Astrophytum''': Species with yellow flowers and fruits with apical dehiscence (e.g., ''A. myriostigma'', ''A. ornatum'').
Occurs in arid to semi-arid environments:
* '''Neoastrophytum''': Species with bicoloured flowers (red/orange centre) and fruits with basal or irregular dehiscence (e.g., ''A. asterias'', ''A. capricorne'', ''A. coahuilense'').
* '''Stigmatodactylus''': Includes only the tuberculate species ''A. caput-medusae''.


== Habitat ==
* desert scrub (matorral)
Astrophytums grow in the Chihuahua Desert, the central plateau of Mexico, and the southern plains of Texas. They are found from 100 m (''A. caput-medusae'') up to 2000 m in altitude. Their habitat varies from rocky grounds and limestone mounds to clay alluvial soils and dry lake beds. They often grow in the shade of grasses and shrubs within the "matorral" vegetation, alongside other Cactaceae and Bromeliads.
* rocky slopes and limestone outcrops
* gravelly and clay alluvial soils
* dry lake beds and ravines
 
Often growing among grasses and shrubs, sometimes partially shaded.
 
Altitude range: approximately 100–2000 m.


== Distribution ==
== Distribution ==
* Mexico (Coahuila, Durango, Guanajuato, Hidalgo, Nuevo León, Querétaro, San Luis Potosí, Tamaulipas, Zacatecas)
North America:
* USA (Texas)
 
* '''Mexico''': Coahuila, Nuevo León, San Luis Potosí, Tamaulipas
* '''United States''': Texas
 
== Taxonomy ==
The genus is well supported as monophyletic.
 
Key points:
 
* Described by Lemaire (1839)
* Closely related to ''Echinocactus'' (excluding ''E. grusonii'')
* Cota & Wallace (1996): phylogenetic proximity to ''Echinocactus''
* Bárcenas et al. (2011): confirmed monophyly
* Hernández-Hernández et al. (2011): supported a distinct clade
* Vázquez-Sánchez et al. (2013): confirmed inclusion of ''A. caput-medusae''
 
The previously proposed genus ''Digitostigma'' is included within ''Astrophytum''.


== Species ==
== Species ==
According to the Joël Lodé index, the genus includes the following 6 recognized species and 2 subspecies:
According to Joël Lodé (2015):


* [[Astrophytum asterias]]
* [[Astrophytum asterias]]
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* [[Astrophytum coahuilense]]
* [[Astrophytum coahuilense]]
* [[Astrophytum myriostigma]]
* [[Astrophytum myriostigma]]
* [[Astrophytum myriostigma subsp. potosinum]]
** [[Astrophytum myriostigma subsp. potosinum]]
* [[Astrophytum myriostigma subsp. tulense]]
** [[Astrophytum myriostigma subsp. tulense]]
* [[Astrophytum ornatum]]
* [[Astrophytum ornatum]]


== Notes ==
== Notes ==
* Molecular studies (Vázquez-Sánchez et al., 2013) have confirmed that ''Astrophytum'' is a monophyletic genus.
 
* The species ''A. caput-medusae'' was originally described under the genus ''Digitostigma'', but is now widely accepted within ''Astrophytum'' despite its atypical morphology.
* One of the most recognizable cactus genera due to its star-shaped morphology.
* Phylogenetic data shows that ''Astrophytum'' is closely associated with ''Echinocactus'', though notably excluding ''Echinocactus grusonii''.
* Highly variable, with numerous described forms, varieties and hybrids.
* The genus is highly popular in cultivation, leading to the creation of countless artificial hybrids and cultivars.
* ''Astrophytum caput-medusae'' represents an extreme morphological deviation within the genus.
* Adapted to environments with irregular rainfall and high temperature fluctuations.


[[Category:Cactaceae]]
[[Category:Cactaceae]]
[[Category:Cactoideae]]
[[Category:Cactoideae]]
[[Category:Cacteae]]
[[Category:Cacteae]]
[[Category:Astrophytum]]

Latest revision as of 08:04, 24 April 2026

Astrophytum
File:Astrophytum myriostigma.jpg
Kingdom Plantae
Family Cactaceae
Subfamily Cactoideae
Tribe Cacteae
SubTribe
Genus Astrophytum
Species
Notes Taxonomy follows Joël Lodé (2015) with molecular support from Cota & Wallace (1996), Bárcenas et al. (2011), Hernández-Hernández et al. (2011), and Vázquez-Sánchez et al. (2013).

Etymology

The name Astrophytum means “star plant”, referring to the star-shaped form of several species.

Description

Astrophytum is a genus of usually solitary cacti with distinctive ribbed or tuberculate bodies and characteristic epidermal trichomes.

  • Habit: Solitary; rarely clustering; globose, flattened or short columnar.
  • Roots: Thickened, adapted to arid conditions.
  • Stems: Green to grey-green, often densely covered with white flaky scales (trichomes).
  • Ribs: Well defined (typically 3–8), or replaced by elongated tubercles in some species.
  • Tubercles: Present only in A. caput-medusae, elongated and irregular.
  • Areoles: Small, often woolly; sometimes bearing spines.
  • Spines: Present or absent depending on species.
  • Flowers: Diurnal, apical, funnel-shaped; yellow, often with red or orange centre; self-sterile.
  • Pollination: By bees.
  • Fruits: Globose, scaly; dehiscent at maturity.
  • Seeds: Brown, helmet-shaped; relatively light.
  • Dispersal: By water (hydrochory) or ants (myrmecochory).

Habitat

Occurs in arid to semi-arid environments:

  • desert scrub (matorral)
  • rocky slopes and limestone outcrops
  • gravelly and clay alluvial soils
  • dry lake beds and ravines

Often growing among grasses and shrubs, sometimes partially shaded.

Altitude range: approximately 100–2000 m.

Distribution

North America:

  • Mexico: Coahuila, Nuevo León, San Luis Potosí, Tamaulipas
  • United States: Texas

Taxonomy

The genus is well supported as monophyletic.

Key points:

  • Described by Lemaire (1839)
  • Closely related to Echinocactus (excluding E. grusonii)
  • Cota & Wallace (1996): phylogenetic proximity to Echinocactus
  • Bárcenas et al. (2011): confirmed monophyly
  • Hernández-Hernández et al. (2011): supported a distinct clade
  • Vázquez-Sánchez et al. (2013): confirmed inclusion of A. caput-medusae

The previously proposed genus Digitostigma is included within Astrophytum.

Species

According to Joël Lodé (2015):

Notes

  • One of the most recognizable cactus genera due to its star-shaped morphology.
  • Highly variable, with numerous described forms, varieties and hybrids.
  • Astrophytum caput-medusae represents an extreme morphological deviation within the genus.
  • Adapted to environments with irregular rainfall and high temperature fluctuations.
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