Elytrigia repens (L.) Desv. ex Nevski
(=Agropyron repens (L.) P. Beauv., Elymus repens (L.) Gould)
Family Poaceae, Tribe Triticeae
NOTE: This species is actionable only when found in field or vegetable seed for planting; tolerance applies.
Spikelet laterally compressed, 8–27 mm long, of 3–8 fertile florets and apical sterile florets, rachilla elongated between florets. Glumes 7–12 mm long, cartilaginous or coriaceous, shorter than spikelet; +/– awned, awn to 3 mm. Fertile florets dorsiventrally compressed, with attached rachilla segment, glabrous or sparsely pubescent; lemma coriaceous, thick and lustrous, 8–13 mm long, awnless or with awn up to 10 mm long; palea 80% length of lemma, keels ciliate, apices emarginated, truncate or rounded. Distal sterile florets resemble fertile florets. Caryopsis oblong, dorsiventrally compressed, with ventral face furrowed and dorsal face rounded, 4.5–5.5 mm long, with apical tuft of hairs; embryo 20–25% length of caryopsis, hilum linear, almost length of caryopsis.
Pascopyrum smithii (Rydb.) Á. Löve [no images provided] (non-FNW)
Elytrigia repens and Pascopyrum smithii are compared below. Note that the characters described are those of the average "best case" florets and do not account for the many variations seen in the florets.
|Character||Elytrigia repens||Pascopyrum smithii|
|rachilla||strap-like, lies flat against palea, sides parallel or only slightly divergent in basal florets||stands away from palea, sides divergent, flares out towards top|
|palea||smoothly concave or with long fold down center||smoothly concave or grooved longitudinally in lower half|
|lemma margins||usually do not extend to keels of palea in lower portion||obscure keels of palea in lower portion|
|lemma above base||with pronounced bulge above base; often slightly keeled just above bulge||with sharp indentation above base; never keeled just above indentation|
widespread in cool north-temperate regions worldwide
native to Europe, northern Africa, and temperate Asia to India
cool temperate climate, grows on most soil types; mountain meadows, cultivated fields, orchards, roadsides, disturbed places
Elytrigia repens is an erect, perennial, rhizomatous grass, up to 1.2 m tall. This species spreads by seed unit and by its extensive system of rhizomes. These well-developed rhizomes are the reason it has become one of the most serious weeds in the north-temperate zone. It significantly reduces the crop yields of many crops in many countries. Also, contamination of commercial crop seed production with quackgrass seed units reduces the value of the harvest. Elytrigia repens is one of ten species covered under the Federal Seed Act for which tolerance is applicable to its introduction (7 CFR 361.6(a)(2)).