Astrebla
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| F. Garbage. ex Benth. |
Astrebla is a genus of plants withinthe sweet grass family (Poaceae). The four species occur only in Australia and arecalled Mitchell Grass there.
description
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Vegetative characteristics
The species are perennial eyrie grasses ( tussock ). The stalks reach heights of 30 to 90 (-120) centimeters. They have a pronounced rhizome with many short, thick, branched rhizomes . The main shoots arise from this rootstock, and the other secondary shoots from these.
The leaf blade is rolled into the bud position. The ligule is a lash line.
Generative characteristics
The inflorescence is a terminal spike or spike-like cluster , which is single or double. The spikelets are sessile, stand individually on the axis. The two to nine flowers per spikelet are hermaphroditic, only the top one is often reduced. The glumes are somewhat uneven, keeled, tapering and oblong to elliptical. The lemmas are longer than the glumes, leathery, deeply three-lobed with a rounded back. Their base is hairy, the midrib ends in a stiff, often curved awn . The palea are shorter than the lemma and have two ciliate keels.
The basic chromosome number is x = 10; 2n = 40, so the plants are tetraploid .
ecology
They are C4 plants . The species are very resistant to drying out and also to grazing (with the exception of horses). They are frost tolerant and can also tolerate occasional fires. They grow on heavy clay soils with no trees.
The clumps are 20 to 30 years old and only fruit once or twice during this time due to the irregular rainfall.
distribution
The genus Astrebla occurs only in Australia and covers around 450,000 km², mainly in western Queensland . The main distribution area is between 18 and 28 ° south latitude. The annual precipitation is between 250 and 550 mm. The four species are often found together and dominate the tussock grasslands .
Systematics
The genus Astrebla was established by Ferdinand von Mueller ex George Bentham .
The genus Astrebla belongs to the tribe Cynodonteae in the subfamily chloridoideae within the family of Poaceae .
There are four species of Astrebla : All four are widespread in Australia.
- Astrebla elymoides F. Muell. ex FMBailey
- Astrebla lappacea (Lindl.) Domin
- Astrebla pectinata (Lindl.) F. Muell.
- Astrebla squarrosa C.E. Hubb.
Importance to humans
The tussock grasslands are heavily grazed today. Typical densities are one sheep on 1.22 hectares. The yield is between 400 and 2250 kg per hectare, depending on the rainfall.
Sources and further information
The article is based on the following sources:
- Grassland Species Profiles of FAO
- Astrebla on New South Wales Flora online .
- Mitchell grass - Australia's own grass ( Memento from June 2, 2009 in the Internet Archive )
Individual evidence
- ↑ Astrebla in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
- ↑ Rafaël Govaerts (ed.): Astrebla. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 18, 2016.
Web links
- L. Watson, MJ Dallwitz: The grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatomy, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. Version: 28th November 2005. ( URL )