Strombocactus

Strombocactus disciformis subsp. disciformis

Strombocactus disciformis is the only species of the monotypic genus Strombocactus in the cactus family ( Cactaceae ). The botanical name ( from Ancient Greek: Strombos = roundabout ( Cactus ), disk-shaped ) refers to the typical growth form of Art

Description

The plants are low, wide, round and unbranched stem and Wurzelsukkulenten of gray - green color. In the habitat they grow disc-shaped, half-hidden in the soil and reach only 2 to 3 cm height diameter of about 8 cm. Plants in cultivation are almost spherical, however. The beet roots grown plants reach 15 cm in diameter and are thus more voluminous than the above-ground parts. The spiral ribs of the plant body are resolved by deep notches in almost warts, which are in the ratio of 13:8 ( close to the golden ratio ). The areoles are sitting on the blunt ends of the bent ( in culture rather straight ), four -edged at the bottom of warts. They rarely carry more than four or five short, bristly spines, which are dropped after a few years.

The either white or cream-colored or magenta flowers are formed from the areoles of the recent warts. They are 2.5 to 3.5 cm long and open yourself up to a diameter of about 4 cm. The 7 mm long, thin and dirty brown when ripe fruits contain 0.3 mm small, reddish-brown seeds.

Distribution, systematics and hazard

Native to Mexico species is divided into two subspecies.

• Strombocactus disciformis ( DC.) Britton & Rose Strombocactus disciformis subsp. disciformis: plants with white flowers from Hidalgo and Querétaro.
• Strombocactus disciformis subsp. esperanzae Glass & S.Arias: plant with magenta flowers from Guanajuato. They are named after Esperanza Benavides de Valásquez who helped with their discovery.

The plants grow in the habitat in columns steep, almost vertical Tonschieferfelsen at altitudes 1000-1600 m above sea level. They are considered at immediate risk ( CITES Appendix I).

DNA analysis revealed a close relationship to the genera Turbinicarpus, Ariocarpus and Pediocactus. Further, duly listed in older literature as to Strombocactus species are either synonyms for Strombocactus disciformis or now belong to Turbinicarpus.

A synonym of Strombocactus disciformis among other Echinocactus turbiniformis Pfeiff. (1838 ). Strombocactus pulcherrimus Halda (1996 ) is still a controversial synonym to Strombocactus disciformis subsp. esperanzae.

In the Red List of Threatened Species IUCN, the type is known as " Vulnerable (VU) ," ie, performed as endangered.