Croton chlorocalyx
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Croton chlorocalyx is a very rare species of the genus Croton in the milkweed family . So far it is only known from the Bangladeshi district of Sylhet in the Sylhet division and has not been found since it was first described in the mid-19th century.
description
Croton chlorocalyx is a small evergreen tree whose very young buds have a hairy, felty surface. Older shoots, however, are smooth. The hairless leaves are elongated to ovate with 6 to 14 thin nerves on each side and a serrated edge. They have a length of 9.5 to 23 and a width of two to six centimeters, with a 0.3 to two centimeter long petiole and a tongue-shaped narrow tip. The inflorescences are three to eight inches long with lateral flowers. The flowering time is not known. Your flower stalks are four to five millimeters long. The five hairy sepals are elongated triangular, two to four millimeters long and about one to three millimeters wide. The five petals are elongated elliptical or spatulate with a length of two to three millimeters and a width of one to one and a half millimeters. The fifteen to sixteen stamens are three to three and a half millimeters long and have elongated anthers about 0.8 millimeters long. The female flowers are on 1.5 to two millimeter long flower stalks. The five sepals are oval or elliptical in shape with serrated edges. They are eight to fifteen millimeters long and four to seven millimeters wide. The five petals are thread-shaped. The ovoid ovary has three pens of 5 to 6.5 millimeters in length. The fruits are not known.
Croton chlorocalyx stands pretty much alone within the genus and can be easily distinguished from almost all other species by the smooth surface of all parts of the plant - with the exception of young buds. The structure of the ovaries is also unusual for the genus.
distribution
The type location of Croton chlorocalyx is in the Sylhet district ( 24 ° 53 ′ 0 ″ N , 91 ° 52 ′ 0 ″ E ) in the division of the same name in northeast Bangladesh. Nothing is known about the habitat.
Hazard and protection
Croton chlorocalyx is extremely rare and could not be found during the entire 20th century. Therefore it is considered critically endangered ( CR ). The most important measure to protect the species is to find it again in nature, followed by securing the habitats and collecting seeds for breeding in botanical gardens.
Systematics
The genus Croton is distributed almost throughout the tropics with more than 1300 species. It belongs to the tribe Crotoneae in the subfamily Crotonoideae within the family Euphorbiaceae .
Initial description
It was first described in 1865 by the Swiss botanist Johannes Müller Argoviensis in the 34th year of the botanical journal Linnaea . The holotype collected by Nathaniel Wallich is in the botanical collection of the Acharya Jagadish Chandra Bose Indian Botanic Garden , the former National Botanical Garden of India in Haora near Kolkata . The species name chlorocalyx is derived from the ancient Greek word χλωρός chlōrós "light green" and "calyx" as the name for the calyx .
Individual evidence
- ↑ a b c d M. K. Pasha: An Evaluation of Endemism and Endemics in Bangladesh Flora . In: Eivin Røskaft and David J. Chivers (Eds.): Proceedings of the International Conference on Biodiversity - Present State, Problems and Prospects of its Conservation. January 8-10, 2011. University of Chittagong, Chittagong 4331, Bangladesh . University of Chittagong 2012, pp. 57-76, ISBN 978-82-998991-0-9 .
- ↑ a b M. K. Pasha, T. Chakrabarty and NP Balakrishnan: A taxonomic revision of Croton L. (Euphorbiaceae) in Bangladesh . In: Journal of Economic and Taxonomic Botany 2013 [2016], Volume 37, No. 2, pp. 379-389, ISSN 0250-9768 .
- ^ A b Johannes Müller Argoviensis : Euphorbiaceae . In: Linnaea 1865, Volume 34, pp. 1-224, here p. 109, digitized .
- ^ A b T. Chakrabarty and NP Balakrishnan: A revision of Croton L. (Euphorbiaceae) for Indian subcontinent . In: Bulletin of the Botanical Survey of India 1992 [1997], Volume 34, pp. 1-88, doi: 10.20324 / nelumbo / v34 / 1992/74421 , ZDB -ID 302898-7 .
- ↑ M. Atiqur Rahman and M. Enamur Rashid: Status of endemic plants of Bangladesh and conservation management strategies . In: International Journal of Environment 2013, Volume 2, No. 1, pp. 231–249, doi: 10.3126 / ije.v2i1.9224 .