Elymus repens

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Elymus repens
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Poales
Family: Poaceae
Subfamily: Pooideae
Genus: Elymus
Species:
E. repens
Binomial name
Elymus repens
Synonyms

Elymus repens, commonly known as couch grass, is a very common perennial species of grass native to most of Europe, Asia, the Arctic biome, and northwest Africa. It has been brought into other mild northern climates for forage or erosion control, but is often considered a weed.

Other names include common couch,[1] twitch, quick grass, quitch grass (also just quitch), dog grass, quackgrass, scutch grass, and witchgrass.[2][3][4][5]

Description

It has creeping rhizomes which enable it to grow rapidly across grassland. It has flat, hairy leaves with upright flower spikes. The stems ('culms') grow to 40–150 centimetres (16–59 in) tall; the leaves are linear, 15–40 centimetres (5.9–15.7 in) long and 3–10 millimetres (0.12–0.39 in) broad at the base of the plant, with leaves higher on the stems 2–8.5 millimetres (0.079–0.335 in) broad. The flower spike is 10–30 millimetres (0.39–1.18 in) long, with spikelets 1–2 centimetres (0.39–0.79 in) long, 5–7 millimetres (0.20–0.28 in) broad and 3 millimetres (0.12 in) thick with three to eight florets. The glumes are 7–12 millimetres (0.28–0.47 in) long, usually without an awn or with only a short one.

It flowers at the end of June through to August in the Northern Hemisphere.[3][4][6][7]

  • Flower spike
    Flower spike
  • Blunt ligule 1mm high, also showing a few very fine hairs of the plant
    Blunt ligule 1mm high, also showing a few very fine hairs of the plant
  • Showing the leaf is dull green, mainly parallel, with auricles and ribbed
    Showing the leaf is dull green, mainly parallel, with auricles and ribbed
  • Rhizomes
    Rhizomes
  • Showing general tufted and visual appearance of the plant
    Showing general tufted and visual appearance of the plant

Taxonomy

Various taxonomic subdivisions of this species have been proposed. Moreover, it is assigned to various genera (Elymus, Elytrigium, Agropyron). In a recent classification, three

variety:[2][3][4]

  • Elytrigia repens subsp. repens. Throughout most of the range of the species.
    • Elytrigia repens subsp. repens var. repens. Awns usually absent or if present, very short.
    • Elytrigia repens subsp. repens var. aristata (Döll) P.D.Sell. Awns present, up to 15 mm long.
  • Elytrigia repens subsp. elongatiformis (Drobow) Tzvelev (syn. Elytrigia elongatiformis (Drobow) Nevski). Central and southwestern Asia, far southeastern Europe (Ukraine).
  • Elytrigia repens subsp. longearistata N. R. Cui. Western China (Xinjiang).

Elytrigia atherica (Elytrigia × drucei Stace), and with the barley species Hordeum secalinum (× Elytrordeum langei (K. Richt.) Hyl.).[3]

Ecology

The foliage is an important forage grass for many grazing mammals.[4] The seeds are eaten by several species of grassland birds, particularly buntings and finches.[8] The caterpillars of some Lepidoptera use it as a foodplant, e.g. the Essex skipper (Thymelicus lineola).

Eradication

Couch grass has become

invasive weed.[2] It is very difficult to remove from garden environments, as the thin rhizomes become entangled among the roots of shrubs and perennials, and each severed piece of rhizome
can develop into a new plant. It may be possible to loosen the earth around the plant, and carefully pull out the complete rhizome. This is best done in the spring, when disturbed plants can recover.[9][10] Another method is to dig deep into the ground in order to remove as much of the grass as possible. The area should then be covered with a thick layer of woodchips. To further prevent re-growth, cardboard can be placed underneath the woodchips. The long, white rhizomes will, however, dry out and die if left on the surface. Many herbicides will also control it.

Applications

The dried

rhizomes of couch grass were broken up and used as incense in medieval northern Europe where other resin-based types of incense were unavailable.[citation needed] Elymus repens (Agropyron repens) rhizomes have been used in the traditional Austrian medicine against fever, internally as a tea, syrup, or cold maceration in water, or externally applied as a crude drug.[11]

References

  1. ^ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
  2. ^ a b c "Elymus repens subsp. repens". Germplasm Resources Information Network. Agricultural Research Service, United States Department of Agriculture. Retrieved 2017-12-15.
  3. ^ a b c d Flora of NW Europe: Elytrigia repens
  4. ^ a b c d Flora of China: Elytrigia repens
  5. ISBN 3-8290-5292-8
  6. ISBN 0-00-219128-8
    .
  7. ^ Hubbard, C. E. Grasses. Penguin Books, 1978
  8. ISBN 0-19-854099-X
    .
  9. ^ "Couch grass / Royal Horticultural Society". Apps.rhs.org.uk. 2012-02-27. Archived from the original on 2012-10-07. Retrieved 2012-10-13.
  10. ISBN 978-0903505628
    .
  11. PMID 23770053
    .

External links

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