Thelocactus leucacanthus
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Thelocactus leucacanthus |
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| Thelocactus leucacanthus | ||||||||||||
| ( Zucc. Ex Pfeiff. ) Britton & Rose |
Thelocactus leucacanthus is a plant from the genus of Thelokakteen in the family of cactus (Cactaceae). The specific epithet leucacanthus means 'with white thorns', from Greek leukos, white and akantha, thorn, sting.
description
Thelocactus leucacanthus grows in groups or as a large multi-headed cushion up to 80 centimeters in diameter. The individual, yellowish green plant bodies are spherical to short cylindrical and reach a height of 4.5 to 15 centimeters and a diameter of 2.5 to 5 centimeters. The 7 to 14 humped ribs run vertically to spirally on the plant body. The conical, up to 1.1 centimeters high humps are rounded at the tip and up to 1.4 centimeters wide and up to 0.8 centimeters long. The areoles up to 6 millimeters long and 3 millimeters wide carry extra-floral nectaries . The single, yellowish white to almost black central spine, which is only sometimes developed, is straight and protruding and can be up to 5 centimeters long. The yellowish white, 6 to 20 radial spines are straight to slightly curved. They reach a length of 7 millimeters.
The yellow to purple or carmine red flowers are up to 5.2 inches long and reach a diameter of 4.5 inches. The pericarpel is covered with scales. The green to yellowish green fruits are up to 9 millimeters long and reach a diameter of up to 8 millimeters. When ripe, the fruits are dry and tear open at the base. They contain seeds up to 2 millimeters long and 1.8 millimeters in diameter . The test cells are polygonal or square.
Distribution, systematics and endangerment
Thelocactus leucacanthus is the southernmost species of the genus. It is distributed at 1200 to 1900 meters in the forest-like succulent bush in the Mexican states of Hidalgo and Querétaro .
It was first described in 1837 as Echinocactus leucacanthus by Ludwig Georg Karl Pfeiffer . Nathaniel Lord Britton and Joseph Nelson Rose introduced the species to Thelocactus in 1923 . There are a lot of invalid double descriptions and recombinations and a multitude of synonyms .
There are two subspecies:
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Thelocactus leucacanthus subsp. leucacanthus :
The nominate form occurs exclusively with yellow flowers. -
Thelocactus leucacanthus subsp. schmollii (Werderm.) Mosco & Zanov. :
It was first described in 1939 as Thelocactus leucacanthus var. Schmollii by Erich Werdermann . Alessandro Mosco and Carlo Zanovello put the variety as a subspecies to Thelocactus leucacanthus in 1999 . The subspecies has only purple to carmine-red flowers.
In the Red List of Threatened Species of the IUCN , the species is listed as " Least Concern (CR) ". H. listed as not endangered.
proof
literature
- Edward F. Anderson : The Great Cactus Lexicon . 2nd Edition. Eugen Ulmer KG, Stuttgart 2011, ISBN 978-3-8001-5964-2 , pp. 623 .
Individual evidence
- ↑ Urs Eggli, Leonard E. Newton: Etymological Dictionary of Succulent Plant Names . Birkhäuser 2004, ISBN 3-540-00489-0 , p. 136.
- ↑ Enumeratio Diagnostica Cactearum hucusque Cognitarum . Berolini 1837, p. 66 (online) .
- ^ NL Britton , JN Rose : The Cactaceae . Descriptions and Illustrations of Plants of the Cactus Family . tape IV . The Carnegie Institution of Washington, Washington 1923, p. 8 ( online ).
- ↑ Flowering cacti and other succulent plants . Vol. 3, 1939, p. 60.
- ↑ Alessandro Mosco, Carlo Zanovello: Cactaceae Consensus Initiatives . No. 7, 1999, p. 18.
- ↑ Thelocactus leucacanthus in the IUCN Red List of Threatened Species 2013.2. Posted by: Gómez-Hinostrosa, C., Sánchez, E., Guadalupe Martínez, J. & Bárcenas Luna, R., 2009. Retrieved December 14, 2013.
