Strombocactus disciformis
| Strombocactus disciformis | ||||||||||||
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Strombocactus disciformis subsp. disciformis |
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| Scientific name of the genus | ||||||||||||
| Strombocactus | ||||||||||||
| Britton & Rose | ||||||||||||
| Scientific name of the species | ||||||||||||
| Strombocactus disciformis | ||||||||||||
| ( DC. ) Britton & Rose |
Strombocactus disciformis is the only plant species of the monotypic genus Strombocactus in the cactus family(Cactaceae). The botanical name (from ancient Greek : Strombos = top (cactus), disc-shaped ) refers to the typical growthhabit ofthe species.
description
The plants are low, broadly round and unbranched stem and root succulents of gray-green color. In their natural habitat they grow disc-shaped, half hidden in the ground and reach a diameter of around 8 cm at a height of only 2 to 3 cm. In contrast, plants in culture become almost spherical. The beet roots of adult plants reach a diameter of 15 cm and are therefore more voluminous than the above-ground parts. The spiraling ribs of the plant bodies are almost dissolved into warts by deep notches, which are in the ratio of 13: 8 (close to the golden ratio ). The areoles sit on the blunt ends of the bent (in culture rather straight), square-edged warts at the bottom. They rarely have more than four or five short, bristly thorns that are shed after a few years.
The either white to cream-colored or magenta-colored flowers are formed by the areoles of the youngest warts. They are 2.5 to 3.5 cm long and open up to a diameter of about 4 cm. The 7 mm long, thin-walled and dirty brown fruits when ripe contain 0.3 mm small, red-brown seeds .
Distribution, systematics and endangerment
The species native to Mexico is divided into two subspecies.
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Strombocactus disciformis (DC.) Britton & Rose
- Strombocactus disciformis subsp. disciformis : plants with white flowers from Hidalgo and Querétaro .
- Strombocactus disciformis subsp. esperanzae Glass & S.Arias : Plants with magenta flowers from Guanajuato . They are named after Esperanza Benavides de Valásquez who helped in their discovery.
The plants grow in the natural locations in columns of steep, almost vertical slate rocks at altitudes of 1000 to 1600 m above sea level. They are considered to be directly endangered ( CITES Appendix I).
DNA analysis revealed a close relationship to the genera Turbinicarpus , Ariocarpus and Pediocactus . Other species listed in older literature as belonging to Strombocactus are either synonyms for Strombocactus disciformis or now belong to Turbinicarpus .
A synonym for Strombocactus disciformis is Echinocactus turbiniformis Pfeiff. (1838). Strombocactus pulcherrimus Halda (1996) is a still controversial synonym for Strombocactus disciformis subsp. esperanzae .
In the Red List of Threatened Species of IUCN is the species as " Vulnerable (VU) ", d. H. listed as endangered.
literature
- Edward F. Anderson : The Great Cactus Lexicon . Eugen Ulmer KG, Stuttgart 2005, ISBN 3-8001-4573-1 , p. 607-608 .
- David Hunt et al .: The New Cactus Lexicon . dh books, 2006, ISBN 0-9538134-4-4 .
- John Pilbeam, Bill Weightman: Ariocarpus et cetera - The special, smaller genera of Mexican cacti . The British Cactus & Succulent Society, 2006, ISBN 0-902099-78-7 .
Individual evidence
- ^ Charles A. Butterworth, J. Hugo Cota-Sanchez, Robert S. Wallace: Molecular Systematics of Tribe Cacteae (Cactaceae: Cactoideae): A Phylogeny Based on rpl16 Intron Sequence Variation . In: Systematic Botany . Volume 27, number 2, 2002, pp. 257-270, PDF .
- ↑ Strombocactus disciformis in the Red List of Threatened Species of the IUCN 2013.2. Posted by: Gómez-Hinostrosa, C., Sánchez, E., Guadalupe Martínez, J. & Bárcenas Luna, R., 2009. Retrieved December 30, 2013.
