''Astrophytum'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of six species of cacti, native to North America. These species are sometimes referred to as living rocks, though the term is also used for other genera, particularly '' Lithops'' (

Aizoaceae The Aizoaceae (), or fig-marigold family, is a large family of dicotyledonous flowering plants containing 135 genera and about 1,800 species. Several genera are commonly known as 'ice plants' or 'carpet weeds'. The Aizoaceae are also referred to a ...

). The generic name is derived from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

words άστρον (''astron''), meaning "star," and φυτόν (''phyton''), meaning "plant."

Description

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 4–10 (rarely 3) 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

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s 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

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s 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.

Species

Synonymy

The genus has several

synonyms A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

: *''Astrophyton'' Lawr., orth. var. *''Digitostigma'' Velazco & Nevárez *''Maierocactus'' E.C.Rost There are a number of species synonyms sometimes seen:

References

"''Astrophytum''"
cactiguide.com. Retrieved July 28, 2005.

"Astromaniacs"
A German / English worldwide forum for fans of ''Astrophytum''

External links

* * {{Taxonbar, from=Q286055 Cacti of North America North American desert flora Cactoideae genera