Poa compressa
Together Depressed bluegrass ( Poa compressa )
The Squeezed bluegrass ( Poa compressa ), also referred to as Platthalmrispe or Flat bluegrass, is a widely used sweet grass ( Poaceae ). A special feature of this plant is its hollow, laterally flattened and thus in cross-section oval blades, and then the kind of epithet takes compressa reference.
Distribution and location
The sweet grass is common in many parts of Europe to Southwest Asia and North Africa from the plains to heights of 1860 m (Alps). It was introduced to North America and is known there as "Canada Bluegrass ". In Germany, the grass comes up frequently absent-minded. It is missing in parts in the north. It grows mainly in pioneer communities on dams, on walls, in gravel pits, on dumps and on ways to open, dry and lean, but mostly calcareous humus and fine earth poor sand, gravel and stone floors.
After Ellenberg it is a full- light plant, sub-oceanic spreading, a Trockniszeiger, a base and Kalkzeiger, nitrogen- poor sites and preferring a Ordnungscharakterart Halbruderaler pioneer and semi- dry grasslands ( Elymetalia ( = Agropyretalia ) repentis ).
Features
The Squeezed bluegrass is a stiff and gray-green, perennial plant, the plant height between 10 and 40, sometimes reaching up to 70 centimeters. The deciduous Hemikryptophyt grows loose Horstig and spreads over wiry rhizomes. The smooth and laterally compressed and thus in cross-section oval stalks grow from the foundation knickig ascending. They carry four to six knots. The smooth leaf sheaths are also compressed, keeled, and therefore ambiguous. The white ligule ( ligules ) are blunt and are 0.5 to 4 millimeters long. The rigid leaf blades are narrowly linear, upper side rough and ending in a teardrop tip. In addition to the midrib ever there is a groove ( ski trail ). The leaves reach less than 6 inches in length. The leaf base is always unbewimpert.
The inflorescences are compact, narrow pyramidal panicles. These measure 1.5 to 10 inches in length and between 0.5 and 3 centimeters in width. They are colored green, yellow-green or purple. The slightly angular and rough branches of the panicle are in pairs or clusters. The three-to zehnblütigen, up to 8 mm long spikelets are densely tufted turn to the Rispenästen. They are ovate to elliptic shaped and compressed. All husks are awnless, keeled and rough around the keels. The three annoying Glumes are slightly unevenly shaped. The lemmas are indistinct five annoying, bald, slightly hairy or sometimes hairy woolly at the base. The caryopses are firmly enclosed by the hardened deck and palea. The flowering period extends from June to August.
Ecology
The Squeezed bluegrass is a perennial Hemikryptophyt (including the two year old ) and a Kriechpionier. The seeds are spread by the wind as a balloon pilot, and reproduction by apomixis has been demonstrated. Vegetative propagation is done by underground runners.
Use, and risk status
In Central Europe it is as forage or pasture grass without meaning, but can be used to Berasung dry slopes. The Squeezed bluegrass is not at risk in Europe and enjoys no special statutory protection (CITES, Bern Convention, BArtSchV ).
In North America, the grass has some value as a pasture grass on poor and dry soils. In some states of the USA, especially Wisconsin, the grass but is considered invasive or potentially invasive species (Virginia, New England). So it penetrates example, in prairies and other natural or rehabilitated grasslands. Due to its strong Rhizomwachstums and the effective seed dispersal negative impact on the natural species composition ( displacement of native flora ) as well as other direct and indirect environmental impacts on communities or habitats are feared.