Hordeum marinum
Beach - barley ( Hordeum marinum )
The beach or dune barley ( Hordeum marinum ) is a sweet grass of the genus of the barley (Hordeum ). It is to be found especially in the area of marine coastal salt marshes or coastal dikes.
- 4.1 subspecies
- 4.2 Genetics
- 8.1 Notes and references
- 8.2 Literature
- 8.3 External links
Description
The beach - barley is an annual, deciduous Therophyt, which reaches heights of growth between 10 and 40 centimeters.
Stems and leaves
The plant grows from the foundation Horstig or individually with a bent base spread to erect ascending and unbranched stems. These are bare and carry three to four nodes. The gray to bluish - green, 1.5 to 8 inches long and 1 to 3.5 cm wide leaves reach up to the ear. You run out into a fine point at the bottom and wear often indistinct small ears. The membranous ligule measure less than 1 millimeter. The leaf sheaths of the upper leaves are bulbous inflated, making them of the similar and closely related mouse barley ( Hordeum murinum ) and the rye - barley ( Hordeum secalinum ) differs with tight-fitting top leaves. The bare, rounded on the back of lower leaf sheaths are soft.
Ears of corn, flowers and fruit
The three to six terminal, green or purple ears are 2-6 inches long, they are surmounted sometimes from the top leaf blade.
As with all single-flowered spikelets of barley growing in threes are stunted alternately on opposite sides of the ears axis while the Gipfelährchen. The mean, sessile flower of flowers triplets is hermaphroditic and clearly formed larger than the two lateral and sterile spikelets. The latter are much smaller and very short-stalked.
All glumes are awned long. The lemmas and the harsh and rigid glumes of the spikelets are not equal. The lower glumes of Seitenährchen are borstlich and reach, including the thin, harsh and straight awn 8-26 mm. The upper glumes are against breitgeflügelt with a 10 to 22 mm long awn. The lemmas are lanceolate and are 3-5 millimeters long, as the awn. The glumes of the central spikelet are both borstlich along its entire length and measure, including the straight awn 10-24 mm. The narrow - ovate, bald, five annoying and rounded on the back lemmas are 6-8 mm long, including the awn about 24 mm.
This fruit is typical of grasses seeded indehiscent fruits ( caryopses ).
The karyotype of the beach - barley is 2n = 14 chromosomes, in addition, there populations of the subspecies H. marinum subsp. gussoneanum with two - and four-fold set of chromosomes.
Dissemination
The distribution area of beach - barley covers Europe, with the exception of the far north, North Africa and West Asia. In Europe, the plant grows mainly along the Atlantic coast and the Mediterranean as well as locally at salt- affected places of the inland. In Scandinavia it is only adventiv before ( introduced ). In Africa, one finds the grass along the northern Mediterranean coast of Algeria, Egypt, Libya, Morocco and Tunisia. The Asian circulation area covers the Arab countries, Armenia, Georgia and Azerbaijan and reaches up to Pakistan to the south and Russia, Kazakhstan, Turkmenistan and Uzbekistan in the north (especially Caspian Sea, Aral Sea ).
The range of the subspecies True beach - barley focused on Southern Europe. The Trockenborstige beach barley is spread to central Europe and was to be found to the coast of the North Sea. Today, the type also applies in the northern states of Germany ( Schleswig -Holstein and Lower Saxony ) in Denmark to be extinct. In Mecklenburg- Western Pomerania, it is impermanent occurring, as in Poland and Lithuania. In the interior of Germany, it occurs synanthropic. It is generally doubted that the deposits are indigenous in Germany and in these neighboring countries, ie may not be part of the beach - barley here for the original or native flora.
Today, both subspecies of beach Barley come introduced before in many parts of North America, especially in the western regions of the United States. Furthermore, the plant was introduced to Australia, Tasmania, New Zealand, the Canary Islands and South Africa.
Ecology
The grass grows mainly in the area of seacoasts on saline soils of salt marshes and mud flats, on sandy beaches on beach ridges or dikes. In North America and in Africa it is often found in the salt steppes of the domestic. She is a Begleitart in the plant communities of Quellerfluren ( Thero - Salicornietea ), and also comes in beach cloves companies ( Armerion maritimae ) ago. The type is not one of the halophytes, for the high saline concentrations are essential to life. Rather, it is more tolerant of high concentrations of ions in the soil and drought, making them over other types at the sites mentioned has a competitive advantage.
The heyday of the beach - barley is in the period from May to July. The pollen from the anthers are blown far superior at this time by the wind and so pollinate the neighboring flowers ( wind pollination ). At the time of seed maturity, dried up the beach - barley. As with other wild barley ( barley weeds ), the ear is fragile and breaks between standing together in groups of three spikelets at seed maturity. This distribution units ( diaspores ) provide for the spread of the plant.
Genetics and systematics
Subspecies
Within the beach barley, two subspecies were identified:
- True beach barley ( Hordeum marinum subsp marinum, Syn. H. maritimum Stokes )
- Trockenborstige beach barley ( Hordeum marinum subsp gussoneanum ( Parl ), Syn. H. hystrix Roth, H. geniculate Allioni )
However, the proven in molecular systematic studies as clearly separate species (H. gussoneanum Parl and H. marinum L.). They also differ in the shape of the glumes. Those of genuine beach barley are unequal. The interiors are halblanzettlich and slightly winged. In contrast, the outer ones are grannenartig. When Trockenborstigen beach barley these are hardly equal and grannenartig.
Genetics
The beach - barley is a body recognized by currently 32 species within the genus Hordeum dar. Due to the high degree of hybridization within the genus and with representatives of closely related species within the grasses, such as types of couch grass ( Elymus ), and the widespread polyploidy it is difficult to draw conclusions about the relationship between species. Thus we find the H. marinum genome, for example, in the hexaploid form of the North American wild barley H. brachyantherum, which was created by a hybridization of a tetraploid H. brachyantherum with a diploid H. marinum after the latter during the last 150 years by Europeans to California has been introduced. In the tetraploid rye - barley (H. secalinum ) and the derived therefrom Kapgerste (H. capense ) there is the genome of the beach - barley, together with the one type of H- genome group, who came from South America or Central Asia either. It is believed that the genome of all the barley species is based on four main types of which are referred to as I, Xa, Xu H. Here, the I-type of Xu type occurs in cultivated barley (H. vulgare) and H. bulbosum, only in the mouse barley and the Xa - type only in the beach - barley before, all other species have the H-type. Studies have shown that there was a speciation within the barley hybrids by phylogenetic studies are difficult.
New molecular - systematic work (Jacob et al. 2007) show that the two subspecies of beach barley have significantly different histories. Since they are also clearly distinguished by a qualitative characteristic and no current gene flow ( intersection ) between two taxa, you should as two separate species (H. marinum and H. gussoneanum ) are performed.
Botanical history
The first description of the beach - barley was carried out by the British botanist William Hudson in his Flora anglica in 1762 synonyms for H. marinum are. :
- H. maritimum Stokes ex Withering
- Critesion marinum ( Huds. ) Á. Löve
- H. geniculate All ..
- H. gussoneanum Parl.
- H. hystrix Roth.
Threats and conservation
The beach - barley is extinct in Germany and Denmark, Einzelsichtungen in Mecklenburg- Vorpommern and Saxony are available, but the species is not established here. The cause for the decline of the species and the extinction of Lower Saxony and Schleswig -Holstein, the lack of flooding of the salt meadows and marshes and the improved coastal protection are considered by the construction of dikes and breakwaters. The beach - barley fails to find sufficient conditions for life on the salt- poor soil and was replaced by competitive strength, salzempfindlichere species. In Europe, the total type is considered frequently and safely, on other continents, it has established itself as a neophyte.
The beach - barley is still protected by the international neither in Germany. It falls neither under the Federal Species Protection Ordinance still under the Fauna-Flora -Habitat Directive (FFH ) of the European Union. The trade is not restricted to the CITES lists does not appear the way.
Use
The beach - barley for hay is not suitable, but can serve as a forage crop for grazing animals, especially domestic sheep.