Elymus repens

Elymus repens (L.) Gould, Madroño 9: 127 1947. (Syn: Agropyron repens (L.) P.Beauv. ……………………………..);

Temp. Eurasia, N. Africa: Afghanistan, Albania, Algeria, Altay, Amur, Austria, Baleares, Baltic States, Belarus, Belgium, Bulgaria, Buryatiya, Central European Rus, China North-Central, China South-Central, Chita, Corse, Cyprus, Czechoslovakia, Denmark, East Aegean Is., East European Russia, East Himalaya, Finland, France, Føroyar, Germany, Great Britain, Greece, Hungary, Iceland, Inner Mongolia, Iran, Iraq, Ireland, Irkutsk, Italy, Kamchatka, Kazakhstan, Khabarovsk, Kirgizstan, Korea, Krasnoyarsk, Krym, Kuril Is., Lebanon-Syria, Libya, Magadan, Manchuria, Mongolia, Morocco, Netherlands, North Caucasus, North European Russi, Northwest European R, Norway, Pakistan, Poland, Portugal, Primorye, Qinghai, Romania, Sakhalin, Sardegna, Sicilia, South European Russi, Spain, Sweden, Switzerland, Tadzhikistan, Tibet, Transcaucasus, Tunisia, Turkey, Turkey-in-Europe, Turkmenistan, Tuva, Ukraine, Uzbekistan, West Himalaya, West Siberia, Xinjiang, Yakutskiya, Yugoslavia; Introduced into: Alaska, Alberta, Antipodean Is., Argentina Northeast, Argentina South, Arizona, Arkansas, Azores, British Columbia, California, Cameroon, Canary Is., Cape Provinces, Caroline Is., Chatham Is., Chile Central, Chile South, Colorado, Connecticut, Crozet Is., Delaware, District of Columbia, Falkland Is., Greenland, Hawaii, Idaho, Illinois, Indiana, Iowa, Japan, Kansas, Kentucky, Kerguelen, Labrador, Madeira, Maine, Manitoba, Marion-Prince Edward, Maryland, Massachusetts, Mexico Central, Mexico Northeast, Mexico Northwest, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Brunswick, New Hampshire, New Jersey, New Mexico, New South Wales, New York, New Zealand North, New Zealand South, Newfoundland, North Carolina, North Dakota, Northwest Territorie, Nova Scotia, Nunavut, Ohio, Oklahoma, Ontario, Oregon, Pennsylvania, Peru, Prince Edward I., Québec, Rhode I., Saskatchewan, South Australia, South Dakota, South Georgia, Tasmania, Tennessee, Texas, Utah, Vermont, Victoria, Virginia, Washington, West Virginia, Western Australia, Wisconsin, Wyoming, Yukon as per POWO;

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Grass for ID : Oman : 141012 : AK-3:
A wild grass seen growing on a mountain slope on 12/3/2010 in Muscat.

Plant was about 2 feet.
… I hope you can identify few of my unidentified posts.

Searched and failed, any kind of dwarf pampas (Cortaderia) grass?

The grass in the background is Agropyron repens. The grass in the foreground with silvery panicle belongs to the genera Stipagrostis, which some authors treat as a subgenera of Aristida. You can see that the central awn is plumose. For species level, kindly refer Flora of Oman Vol.4. Otherwise send a close up of the spikelet.