Boucerosia
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| Wight & Arn. |
The plant genus Boucerosia belongs to the subfamily of the silk plants (Asclepiadoideae) in the family of the dog poison plants (Apocynaceae). The flowers of these succulent plants give off an unpleasant odor. For example, Boucerosia frerei is used as an ornamental plant.
description
The species Boucerosia frerei , which used to be classified in its own genus, Frerea Dalzell , differs from the other species in many features.
Vegetative characteristics
Boucerosia species grow as little to richly branched trunk succulent plants . The succulent, 0.3 to 2 cm wide, green cylindrical shoot axes are smooth, have four sharp or rounded edges and reach heights of 2 to 12 cm and stand together in groups or crawl individually and can then be up to 20 cm long. They contain clear milky juice .
The scales, which are usually 0.1 to 0.3 cm long and 0.1 to 0.15 cm wide, stalked or sessile, succulent leaves fall off quickly in some species. Only in Boucerosia frerei are the leaves not reduced, but rather normal leaf blades 2 to 3 cm long and 1 to 1.2 cm wide. If stipules are present then they are ovate or, in Boucerosia frerei, transformed into glands.
Inflorescences and flowers
The more or less sessile flowers are in Boucerosia frerei individually on the internodes, but usually three to 60 in terminal, on smooth inflorescence axes, standing, pseudodold-like inflorescences , with one to 40 flowers open at the same time. The flowers , which smell unpleasantly of excrement, are hermaphroditic, radial symmetry , five-fold with a double perianth . The five free sepals are shorter than the corolla tube and the edges are hairless. The five fleshy petals , 5 to 15 mm long, are flat to bell-shaped only at their base or between one to three quarters of their length. The edges of the corolla lobes are flat or curved back and smooth or ciliate. The inside of the petals is green, white to cream to yellow, monochrome or from purple to brown to reddish stripes, with warts, smooth, papilose or hairy on the whole surface or in the area of the corolla tube. The outside of the petals is green. The "gynostegium" is serene. The purple corolla is divided into the staminal and interstaminal corona . The upright pollinia are D-shaped. There are two smooth, free, upper carpels . The scar head is white. No nectar is produced.
Fruits and seeds
The follicles , usually in pairs, arranged upright at an acute angle to each other, are smooth, pencil-shaped, slender with a diameter of 4 to 6 mm and often quite long at 6.5 to 10 (rarely up to 15) cm. The medium-brown seeds are egg-shaped, about 8 mm long and about 4 mm wide. They are wingless (in contrast to some closely related genera) and have 1 to 3 cm long, pure white flying hairs.
Chromosome numbers
The chromosome numbers are 2n = 22 (found in Boucerosia crenulata , Boucerosia diffusa ), or 44 (in Boucerosia frerei ).
Systematics and distribution
The distribution area in southern Asia extends from India and Sri Lanka via Nepal to Myanmar .
The generic name Boucerosia was first published in 1834 by Robert Wight & George Arnott Walker Arnott in Robert Wight: Contributions to the Botany of India , 34. The type species is Boucerosia umbellata (Haw.) Wight & Arn. In 1990 MG Gilbert presented the species in a subgenus Caralluma in Bradleya - Yearbook of the British Cactus and Succulent Society , 8, p . Boucerosia (Wight & Arn.) MGGilbert . The genus Caralluma R.Br. was divided into eight genres by Darrel Charles Herbert Plowes in 1995. Boucerosia Wight & Arn. was reactivated. For Boucerosia Wight & Arn. there are the synonyms Frerea Dalzell and Hutchinia Wight & Arn.
The genus Boucerosia belongs to the Subtribus Stapeliinae from the tribe Ceropegieae in the subfamily Asclepiadoideae within the family Apocynaceae .
There are about seven Boucerosia typologies:
- Boucerosia crenulata Wight & Arn. : It occurs from India to Myanmar.
- Boucerosia diffusa Wight : It occurs in southern India.
- Boucerosia frerei (Rowley) Liede & Meve (Syn .: Frerea indica Dalzell ): It occurs in India.
- Boucerosia indica (Wight & Arn.) Plowes (Syn .: Hutchinia indica Hook. F. , Boucerosia hutchinia Decne. ): It occurs in India.
- Boucerosia pauciflora Wight : It occurs in southeast India.
- Boucerosia procumbens (Gravely & Mayur.) Plowes : It occurs in southwest India.
- Boucerosia umbellata (Haw.) Wight & Arn. : It occurs in India, Sri Lanka and from Bangladesh to Myanmar.
According to R. Govaerts, this genus is no longer included:
- Boucerosia edulis Edgew. => Caudanthera edulis (Edgew.) Meve & Liede
- Boucerosia russeliana Courbai ex Brongn. => Desmidorchis retrospiciens Ehrenb.
swell
- Sigrid Liede-Schumann & Ulrich Meve: The Genera of Asclepiadoideae, Secamonoideae and Periplocoideae (Apocynaceae) , 2006: On the genus Boucerosia - Online at INTKEY databases of the DELTA System . (Section description and systematics)
- Ulrich Meve & Sigrid Liede-Schumann: A molecular phylogeny and generic rearrangement of the stapelioid Ceropegieae (Apocynaceae-Asclepiadoideae). , in Pl. Syst. Evol. , 234, 2002, pp. 171-209.
Individual evidence
- ^ Robert Wight: Contributions to the Botany of India , 1834, p. 34. Scanned online.
- ^ Darrel Charles Herbert Plowes: A reclassification of Caralluma R. Brown (Stapelieae: Asclepiadaceae). in Haseltonia , 3, 1995, pp. 49-70.
- ↑ Ulrich Meve & Sigrid Liede-Schumann: A molecular phylogeny and generic rearrangement of the stapelioid Ceropegieae (Apocynaceae-Asclepiadoideae). Pl. Syst. Evol. , 234, 2002, pp. 171-209.
- ↑ a b c d e f g h Rafaël Govaerts (Ed.): Boucerosia - World Checklist of Selected Plant Families des Royal Botanic Gardens, Kew. Last accessed on November 9, 2018.
