Alexgeorgea

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Alexgeorgea
Alexgeorgea buried flowers.jpg

Alexgeorgea

Systematics
Class : Bedecktsamer (Magnoliopsida)
Monocots
Commelinids
Order : Sweet grass (Poales)
Family : Restionaceae
Genre : Alexgeorgea
Scientific name
Alexgeorgea
Carlquist

Alexgeorgea is a plant kind from the family of Restionaceae that occurs with three species in Western Australia. It was described by Sherwin Carlquist in 1976and named after the Australian botanist Alexander Segger George .

features

Celestial part of a male (left) and female (middle) plant, as well as the stylus of a female flower protruding above the surface of the earth

The plants grow with elongated, whitish rhizomes that are about 10 centimeters below the surface of the earth and have shiny leaf scales. The rhizome occasionally branches out, especially in the places where the photosynthetically active green shoots rise above the surface of the earth . These have close-fitting leaf sheaths , are longitudinally striped and can be downy hairy. They either have short, flattened side rungs or are cylindrical and branched several times. Alexgeorgea are dioeciously separated sexes ( diocesan ). The male plants have multi-flowered spikelets at the end of the shoot. A specialty of the genus are the spikelets of the female plants, which sit directly on the rhizome with a single flower, so that only the tips of the shiny bracts and the three long, purple-red stylus protrude above the surface of the earth. The unilocular ovary forms a 10 to 15 millimeters in size, spherical or inverted-cone-shaped after fertilization nut fruit .

ecology

Alexgeorgea species grow in sandy soil in moderately moist or seasonally dry areas, often on ruderal areas . The reproduction probably takes place mainly vegetatively through the growth of the rhizomes. The flowers are pollinated by the wind. During germination, the seedling pushes the fruit upwards without it reaching the surface of the earth and forms an upwardly protruding sprout and shortly afterwards the first rhizome. The subterranean location of the female flowers, as well as the underground germination, could be adaptations to the frequent fires in Western Australia.

Systematics

Within the Restionaceae, the genus Alexgeorgea is assigned to the subfamily Leptocarpoideae and here to the Loxocarya group. Three species are described within the genus, all of which only occur in Western Australia :

literature

  1. ↑ a b c Sherwin Carlquist: Alexgeorgea a Bizarre New Genus . In: Australian Journal of Botany . tape 24 , no. 2 , 1976, p. 281–295 (English, full text [PDF]).
  2. ↑ Klaus Kubitzki, Herbert Huber: Flowering plants, Monocotyledons: Alismatanae and Commelinanae (except Gramineae) . Springer, Berlin, Heidelberg 1998, ISBN 3-540-64061-4 , pp. 440 .
  3. ↑ Barbara G. Briggs, H. Peter Lindner: A new subfamilial and tribal classification of Restionaceae (Poales) . In: Telopea . tape 12 , no. 3 , 2009, p. 333–345 (English, full text [PDF; 240 kB ]).
  4. ↑ Rafaël Govaerts (ed.): Alexgeorgea. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 13, 2018.

Web links

Commons : Alexgeorgea  - collection of images, videos and audio files