Cornus volkensii

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Cornus volkensii
Systematics
Nuclear eudicotyledons
Asterids
Order : Dogwood-like (Cornales)
Family : Dogwood family (Cornaceae)
Genre : Dogwood ( Cornus )
Type : Cornus volkensii
Scientific name
Cornus volkensii
Harms

Volkensii Cornus is a plant from the genus of dogwood ( Cornus ) within the family of Dogwood (Cornaceae). Their distribution area is in tropical East Africa . There he is called "Mnyandege" or "Msese".

description

Cornus volkensii grows as an evergreen tree that reaches heights of 18 to 25 meters. The gray-black bark is somewhat hairy on young branches and becomes bare on older branches.

The against-constantly arranged at the branch leaves are divided into petiole and leaf blade. The petiole measures about 2 centimeters. The entire-margined and simple leaf blade is 5 to 18 centimeters long and 3 to 6 centimeters wide, oval or narrow-oval to lanceolate, wedge-shaped at the base. The leaves are also hairy when they shoot.

Cornus volkensii is the only dioecious separate-sex ( dioecious ) Cornus species. The yellowish, hairy, four-fold flowers are close together in several terminal heads. Characteristic of Cornelian cherries, the inflorescences are framed by four decrepit bracts . The male flowers are in zymose inflorescences , almost golden, the female inflorescences are real umbels . In the male flowers a rudiment of the gynoceum can still be seen, the female flowers have four stamen remains. The pollen is - unique in the genus Cornus - prickly on the outside.

The stone fruits are purple-black when ripe.

distribution

Cornus volkensii is distributed in tropical East Africa, in Burundi , Kenya , Congo , Malawi , Mozambique , Rwanda , Uganda , Zimbabwe and Tanzania . Cornus volkensii occurs in the montane altitude range of the "Eastern Arc Mountains", at altitudes of 1200 to 3000 meters.

It grows there in evergreen forests, often on the edge of streams. It belongs to the topmost canopy layer or to the emergent that rise above the other treetops. It is associated with trees from the genera Allophylus and Podocarpus , as well as with Aphloia theiformis , Cassipourea gummiflua , Chrysophyllum gorungosanum , Ficalhoa laurifolia , Garcinia buchananii , Hagenia abyssinica , Maesa lanceolata and Neoboutonia macrocalyx . The bamboo Sinarundinaria alpina grows in the undergrowth, the liana Schefflera goetzenii is common .

use

Cornus volkensii is used as a supplier of wood and is occasionally planted as a shade provider. The leaves are used as medicine .

Systematics

The first description of Cornus volkensii was by Harms . The specific epithet volkensii honors Georg Volkens , who collected plants on Kilimanjaro from 1892 to 1894 .

Within the genus Cornus , Cornus volkensii is related to the species of the subgenus Cornus , the Cornelian cherries. The differences to the other Cornelian cherries were already seen as so serious that Cornus volkensii was not only placed in its own subgenus, but even in its own genus Afrocrania . This concept, which provided for the division of the genus into numerous very small units, is not very widespread. Investigations of the DNA showed that Cornus volkensii represents a basal line of the Cornelian cherries alongside Cornus sessilis . Starting from an evolutionary center in Europe, their ancestors migrated to Africa around 43 to 50 million years ago. The following representation of the relationships between the Cornelian cherries results:

   
   
   
   

 Cornus mas


   

 Cornus officinalis



   

 Cornus chinensis


   

 Cornus eydeana




   

 Cornus volkensii



   

 Cornus sessilis



Individual evidence

  1. ↑ Mark A. Hyde, Bart Wursten: Species information - Afrocrania volkensii . In: Flora of Zimbabwe . London 2008.
  2. ↑ Volkens, Georg . In: Heinrich Schnee (Ed.): German Colonial Lexicon . tape 3 . Quelle & Meyer, Leipzig 1920, p. 630 .
  3. ↑ IK Ferguson: World pollen and spore flora . Vol. 6. Cornaceae. Almqvist & Wiksell, Stockholm 1977. quoted from Xiang et al: Cornus eydeana (Cornaceae), A New Cornelian Cherry from China - Notes on Systemtics and Evolution . In: Systematic Botany. Laramie Wyo 28.2003, 4, 757-764. ISSN 0363-6445
     
  4. ^ Jan Schipper, Neil Burgess: Eastern Arc forests. In: worldwildlife.org. 2001, accessed March 26, 2008 .
  5. ↑ Daniel J. McKone, Vincent P. Walzem: A Brief Survey of the Catchment Forest Reserves of the Mbeya Region, Tanzania. (No longer available online.) In: mckone.org. August 1994, archived from the original on September 29, 2007 ; accessed on August 30, 2015 (in the web archive).
  6. ^ Andreas Hemp: Vegetation of Kilimanjaro, hidden endemics and missing bamboo . In: African Journal of Ecology . tape 44 , 3 (Sept.), 2006, ISSN  0141-6707 , pp. 305-328 , doi : 10.1111 / j.1365-2028.2006.00679.x .
  7. ↑ Mark A. Hyde, Bart Wursten: Species information - Afrocrania volkensii . In: Flora of Zimbabwe . London 2008.
  8. ↑ Volkens, Georg . In: Heinrich Schnee (Ed.): German Colonial Lexicon . tape 3 . Quelle & Meyer, Leipzig 1920, p. 630 .
  9. ^ Richard H. Eyde: The case for keeping Cornus in the broad Linnaeaen sense . In: Systematic Botany . tape 12 , 1987, ISSN  0363-6445 , pp. 505-518 .
  10. ↑ Qiu-Yun (Jenny) Xiang, Steve R. Manchester, David T. Thomas, Wenheng Zhang: Phylogeny, Biogeography, and Molecular Dating of Cornelian Cherries (Cornus, Cornaceae). Tracking Tertiary Plant Migration . In: evolution . tape 59 , no. 8 , 2005, ISSN  0014-3820 , p. 1685-1700 .

literature

  • Jon C. Lovett, Chris K. Ruffo, Roy E. Gereau, James RD Taplin: Field Guide to the Moist Forest Trees of Tanzania. (No longer available online.) In: york.ac.uk. Archived from the original on April 14, 2005 ; accessed on August 30, 2015 (in the web archive).
  • JFM Cannon: Cornaceae . In: Flora Zambesiaca . tape 4 . London 1978 ( kew.org ).

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