Cololejeunea khanii
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Holotype of Cololejeunea khanii in the Muséum national d'histoire naturelle , Paris |
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| Cololejeunea khanii | ||||||||||||
| P.Tx. |
Cololejeunea khanii is a liverwort species from the Lejeuneaceae family . The species is rare and endemic to the Chittagong Hill Tracts in Bangladesh , where itlivesas an epiphyte on the bark of deciduous trees .
features
The yellow-green plants, up to 12 millimeters long, form depressed lawns on their substrate. The irregular, densely branched stems are 1.4 to 1.9 millimeters wide and have a stem diameter of 70 to 85 micrometers. The cross section contains five to six cortical cells 17 to 30 by 20 to 28 micrometers in size and one medullary cell 24 by 18 micrometers in size. The overshot double-lobed flank leaves are at an angle of 60 ° to 90 ° to the stem. The approximately oval, slightly sickle-shaped upper leaves have a length of 0.65 to 1.0 millimeters and a width of 0.4 to 0.5 millimeters. Their thin-walled marginal leaf cells are 9 to 22 by 8 to 14 micrometers in size, the basal ones from 30 to 55 by 17 to 26 micrometers. The bubble-shaped oval lower leaves have a length of two fifths to two sevenths of the upper leaves. The stems are three to four cells long.
Cololejeunea khanii is monoecious . The archegonium has an egg cell and unequal bilobed bracts 0.3 to 0.5 millimeters long and 0.17 to 0.27 millimeters wide and 0.25 to 0.35 millimeters long and 0.08 to 0.15 millimeters wide . The perianthia are obovoid (inverted egg-shaped) and strongly flattened with three longitudinal keels and a rounded tip, they are 0.46 to 0.58 millimeters long and 0.56 to 0.82 millimeters wide.
Cololejeunea khanii is very similar to Cololejeunea trichomanis , but differs from this species in the keels of the perianthia, two of which have pronounced horn-like outgrowths. The statement by Pierre Tixier in his first description that the perianthia are folded five times is misleading.
Location requirements
Cololejeunea chittagongensis is only known from the bark of deciduous trees.
distribution
In the first description, a forester's house in Upazila Kaptai ( 22 ° 30 ′ 0 ″ N , 92 ° 13 ′ 0 ″ E ) is given as the locus classicus . The Upazila Kaptai is located in the Rangamati District , Chittagong Division , in it is the dam of the Karnaphulisau . Another location is located in the valley of Sangu ( 22 ° 12 '0 " N , 92 ° 7' 0" O ), where Cololejeunea khanii was found in the shady forest to 120 meters above sea level on the branches of citrus trees. The species is endemic to Bangladesh.
Hazard and protection
Cololejeunea khanii is very rare and is considered an endangered species because of its limited range and the anthropogenic impairment of its habitat.
Systematics
The Lejeuneaceae family is the most extensive family of liverworts and the class Jungermanniopsida with more than 1000 species in more than 90 genera . In it, Cololejeunea is the sister taxon to Aphanolejeunea and by far the most extensive genus. Due to the often only minor morphological differences and the great intraspecific variability, the genus, like the whole family, is taxonomically difficult to process.
The holotype and several other specimens of Cololejeunea khanii were initially included in Pierre Tixier 's personal collection . Today they are in the collection of the Muséum national d'histoire naturelle in Paris.
literature
- Pierre Tixier: Bryophytae Indosinicae . In: Dacca University Studies, Part B, Science 1967, Volume 15, pp. 1-14 (first description, in Latin and French).
Individual evidence
- ↑ a b c d Rui-Liang Zhu, Min Zheng and Xin Zhao: Taxonomic studies on the genus Cololejeunea (Lejeuneaceae, Hepaticae) I. Notes on several little known species of Asia and Oceania . In: Nova Hedwigia 2004, Volume 79, No. 3-4, pp. 527-535, doi: 10.1127 / 0029-5035 / 2004 / 0079-0527 .
- ↑ Tomas Hallingbäck: Report from the Asian Bryophyte Conservation Workshop Held in Singapore, Feb 28 - 2 March 2008 . In: The Bryological Times 2009, No. 128, pp. 20-26, digitized .
- ^ S. Robbert Gradstein, M. Elena Reiner-Drehwald and Harald Schneider: A phylogenetic analysis of the genera of Lejeuneaceae (Hepaticae) . In: Botanical Journal of the Linnean Society 2003, Volume 143, No. 4, pp. 391-410, doi: 10.1111 / j.1095-8339.2003.00235.x .
- ↑ Cololejeunea khanii Tixier , website of the Muséum national d'histoire naturelle , accessed on May 9, 2019.