Orbea decaisneana
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Orbea decaisneana |
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| Orbea decaisneana | ||||||||||||
| ( Lem. ) Bruyns |
Orbea decaisneana ( Syn .: Caralluma decaisneana ) is a species of the subfamily of the silk plants (Asclepiadoideae).
features
Habit and vegetative characteristics
The upright, stem succulent shoots form mats with a diameter of up to 50 cm. Occasionally, rhizome-like, underground shoots are also formed. The shoots are relatively slender, cylindrical and taper towards the tip of the shoot. They are 10 to 40 cm high and 1.5 cm in diameter. The gray-green surface is marbled or spotted brown. The warts are 10 to 15 mm long and arranged in four obtuse-angled rows with clearly grooved sides. 3 to 6-ribbed specimens are also less common. The strong warts are conical-sub-like, horizontally splayed to ascending and form a very slender tip without stipules .
Inflorescence and flowers
One to three inflorescences are formed per shoot near the tip of the shoot. Each inflorescence with a pillow-shaped stem gradually develops one to five, rarely up to ten, upright flowers. The small lanceolate or thread-like bracts are up to 1 mm long. The flower stalk becomes one to five mm long with a diameter of 1.5 to 2 mm (rarely up to 3 mm). The lanceolate, pointed sepals are three to five millimeters long and 1.5 mm wide at the base. The bell-shaped corolla is 0.8 to 1.5 cm long and 1.5 to 2.5 cm in diameter. The outside is cream colored with brown spots. Inside it is dark purple or reddish brown, sometimes turning yellowish towards the base of the corolla tube. The top is covered with small papillae , each of which has a fine white bristle at the tip. The cup-shaped corolla tube with a pentagonal cross-section is four to six millimeters long and six to eight millimeters in diameter. Occasionally the corolla is somewhat thickened around the mouth of the corolla tube. The ovate-lanceolate petals are 7 to 12 mm long and 5.5 to 7 mm wide at the base. You first rise a little to then spread. The top is slightly convex, the edges are slightly turned over and show no cilia . The purple-colored to flesh-colored, and sessile pentagonal in cross section Nebenkrone is high 4 mm, and measures 5 to 5.5 mm in diameter. The outer, bag-shaped corolla lobes are 2 mm long, the edge of the bag is lower in the center than on the sides and too often notched towards the tip. Here they are fused with the bases of the inner corolla lobes. The inner, one millimeter long, right-angled and dorsoventrally flattened corolla lobes are pressed against the back of the anthers , then rise and protrude above the stylus head. The blunt to pointed tip ends sometimes even touch above the stylus head. Basally, the tips are somewhat wrinkled.
Geographical distribution
The species is distributed along the southern and western fringes of the Sahara in Algeria , Burkina Faso , Mali , Morocco , Senegal and Sudan on higher mountains, but also in the desert itself. It occurs from above sea level to about 2000 m above sea level. It grows there on dry grassland (Senegal), between stones on the granite massifs of the Hoggar Mountains and on limestone along the Moroccan coast. Here it is sometimes in association with the dwarf palm ( Chamaerops humilis L.) and Euphorbia beaumeriana Cosson & Hook. f. (Rauh 1972). Audissou found them from Essaouira to Sidi Ifni "and up to 150 km inland" ( Aoulouz , Souss-Massa-Draâ region ). In 1929 there was still a population in the eastern Rif Mountains , which is now probably extinct. He found the species often associated with the argan tree ( Argania spinosa , Sapotaceae), Senecio anteuphorbium , Warionia saharae (Asteraceae) and Acacia gumifera (Mimosaceae).
Systematics
The taxon was first published in 1844 by Antoine Charles Lemaire under the Basionym Boucerosia decaisneana . It was later recombined five times before it was placed in the genus Orbea by Peter Vincent Bruyns . It is the type of the genus Angolluma Munster , which was only established in 1990, but was synonymous with Orbea by Bruyns in 2001 . There may still be two synonyms , Caralluma hesperidum Maire , which was recently recombined in Angolluma and Caralluma venenosa Maire , which was also recently placed under Angolluma . However, the former taxon was recently raised again to the rank of a subspecies, so that there are currently two subspecies:
- Orbea decaisneana (Lem.) Bruyns subsp. descaisneana .
- Orbea decaisneana (Lem.) Bruyns subsp. hesperidum (Maire) Jonkers : It occurs in Morocco.
supporting documents
Individual evidence
- ^ A b Jean-André Audissou: Moroccan Stapeliads. Asklepios, 94: 18-27, 2005 PDF
- ↑ Keith Bensusan: Taxonomy and conservation status of Moroccan stapeliads (Apocynaceae-Asclepiadoideae-Ceropegieae-Stapeliinae). Bulletin de l'Institut Scientifique, Rabat, section Sciences de la Vie, 31 (2): 67-77, Rabat 2009 PDF
literature
- Birgit Müller, Janine Kiel, Focke Albers, Ulrich Meve: Orbea . In: Focke Albers, Ulli Meve (Hrsg.): Succulents Lexicon Volume 3 Asclepiadaceae (silk plants). Pp. 189-208, Ulmer, Stuttgart 2002 ISBN 978-3-8001-3982-8 .
- Peter V. Bruyns: Monograph of Orbea and Ballyanthus (Apocynaceae - Asclepiadoideae - Ceropegieae) . In: Systematic Botany Monographs . Volume 63, pp. 1-196, American Society of Plant Taxonomists, Ann Arbor 2001, ISBN 0-912861-63-0 .
