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Astrophytum myriostigma
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Caryophyllales
Family: Cactaceae
Subfamily: Cactoideae
Tribe: Cacteae
Genus: Astrophytum
Type species
Astrophytum myriostigma

A. asterias
A. capricorne
A. caput-medusae
A. coahuilense
A. myriostigma
A. ornatum[2]

Astrophytum is a genus of six species of cacti, native to North America.[2]

These species are sometimes referred to as living rocks, though the term is also used for other genera, particularly Lithops (Aizoaceae). The generic name is derived from the Greek words άστρον (astron), meaning "star," and φυτόν (phyton), meaning "plant."


The species of the genus Astrophytum usually grow individually with spherical to columnar green shoots and reach heights of up to 1.5 meters. The shoots are often densely covered with fine white tufts of hair, but sometimes they are completely bald. There are four to ten (rarely three) very noticeable ribs that are not divided into cusps. The large areoles stand close together, but do not merge. The spike is variable. Spines may be present or may be missing entirely.

The funnel-shaped, large flowers are yellow or yellow with a red throat. They appear at the top of the shoots and open during the day. The pericarpel is covered with pointed scales. The cap-shaped seeds have a diameter of up to 2.5 millimeters with a brownish black seed coat which is almost smooth. The edge is rolled towards the sunken hilum.


Image Hi Common Name Distribution
Astrophytum asterias (Zucc.) Lem. Sand dollar cactus, sea urchin cactus, star peyote small parts of Texas in the United States and Mexico.
Astrophytum capricorne (A.Dietr.) Britton & Rose Goat's horn cactus Coahuila regions of Northern Mexico.
Astrophytum caput-medusae D.R.Hunt Nuevo León, Mexico
Astrophytum coahuilense (H.Moeller) Kanfer Coahuila and Durango, Mexico
Astrophytum myriostigma Lem. Bishop's cap cactus, bishop's hat, bishop's mitre cactus northeastern and central Mexico.
Astrophytum ornatum (DC.) Britton & Rose – Monk's hood[2] bishop's cap or monk's hood cactus Central Plateau of Mexico.
Seedlings of Astrophytum spp.
A ripe fruit of A. caput-medusae with seeds and testa showing


The genus has several synonyms:

  • Astrophyton Lawr., orth. var.
  • Digitostigma Velazco & Nevárez
  • Maierocactus E.C.Rost[1]

There are a number of species synonyms sometimes seen:

Name Synonym of
Astrophytum columnare Astrophytum myriostigma
Astrophytum crassispinoides Astrophytum capricorne var. crassispinoides
Astrophytum glabrescens Astrophytum ornatum
Astrophytum niveum Astrophytum capricorne var. niveum
Astrophytum nuda Astrophytum myriostigma var. nudum
Astrophytum prismaticum Astrophytum myriostigma
Astrophytum senile Astrophytum capricorne
Astrophytum tulense Astrophytum myriostigma


  1. ^ a b "Astrophytum asterias (Zucc.) Lem". Germplasm Resources Information Network. United States Department of Agriculture. 2004-02-23. Retrieved 2010-08-08.
  2. ^ a b c "Species Records of Astrophytum". Germplasm Resources Information Network. United States Department of Agriculture. Retrieved 2010-08-08.

External links[edit]