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agrostide stolonifere, carpet bentgrass, creeping bent, creeping bentgrass, fiorin, redtop, spreading bent

bentgrass, spike bent, spike bent grass

Habit Plants perennial; stoloniferous, stolons 5-100+ cm, rooting at the nodes, often forming a dense mat, without rhizomes. Plants perennial; usually cespitose, sometimes rhizomatous, not stoloniferous.
Culms

(8)15-60 cm, erect from a geniculate base, sometimes rooting at the lower nodes, with (2)4-7 nodes.

8-100 cm, erect or decumbent at the base, sometimes rooting at the lower nodes, with (2)3-6(8) nodes.

Leaves

mostly cauline;

sheaths smooth;

ligules longer than wide, dorsal surfaces usually scabrous, rarely smooth, apices usually rounded, acute to truncate, erose to lacerate, basal ligules 0.7-4 mm, upper ligules 3-7.5 mm;

blades 2-10 cm long, 2-6 mm wide, flat.

mostly cauline;

sheaths smooth or slightly scabrous;

ligules (1)1.7-8(11.2) mm, dorsal surfaces scabrous, apices truncate to obtuse, lacerate to erose;

blades 4-15 cm long, 2-7 mm wide, flat.

Panicles

(3)4-20 cm long, less than 1/2 the length of the culm, 0.5-3(6) cm wide, narrowly contracted, dense, oblong to lanceolate, exserted from the sheaths at maturity, lowest node with 1-7 branches;

branches scabrous, ascending to appressed, except briefly spreading during anthesis, usually some branches at each node spikelet-bearing to the base, lower branches 2-6 cm;

pedicels 0.3-3.3 mm.

(3)5-30 cm long, 0.5-4 cm wide, contracted, spikelike, oblong, or lanceolate, usually dense, rarely more open, sometimes interrupted near the base, bases usually exserted, rarely enclosed by the upper sheaths at maturity, lowest node with 1-5 branches;

branches scabrous, ascending to appressed, spikelet-bearing to or near the base, usually hidden by the spikelets, spikelets crowded, lower branches 1-2(4) cm;

pedicels 0.2-4.3 mm.

Spikelets

lanceolate, green and slightly to strongly suffused with purple.

lanceolate to narrowly ovate, greenish to purplish.

Glumes

subequal to unequal, 1.6-3 mm, lanceolate, 1-veined, sometimes scabridulous distally, at least on the midvein, acute to acuminate or apiculate;

callus hairs to 0.5 mm, sparse;

lemmas 1.4-2 mm, opaque to translucent, smooth, 5-veined, veins obscure or prominent distally, apices acute to obtuse, entire or the veins excurrent to about 0.1 mm, usually unawned, rarely with a subapical straight awn to about 1 mm;

paleas 0.7-1.4 mm, veins visible;

anthers 3, 0.9-1.4 mm.

subequal to equal, 1.5-3.5 mm, scabrous on the midvein and sometimes on the back, 1(3)-veined, acute, elongate-acuminate, with an awnlike tip to 1 mm;

callus hairs to 0.3 mm, sparse to abundant;

lemmas 1.2-2.2 mm, smooth, translucent to opaque, 5-veined, veins prominent distally or obscure throughout, apices acute, entire or toothed, teeth no more than 0.12 mm, unawned or awned from above midlength, awns to 3.5 mm, straight or geniculate;

paleas absent or to 0.5 mm;

anthers 3, 0.3-0.6 mm.

Caryopses

0.9-1.3 mm;

endosperm solid.

0.9-1.2 mm;

endosperm solid or soft.

2n

= 28, 35,42.

= 28, 42, 56.

Agrostis stolonifera

Agrostis exarata

Distribution
from FNA
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; HI; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; Greenland
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AZ; CA; CO; ID; KY; MT; NE; NM; NV; OK; OR; SD; TX; UT; VT; WA; WY; AB; BC; NT; SK; YT
[WildflowerSearch map]
[BONAP county map]
Discussion

Agrostis stolonifera grows in areas that are often temporarily flooded, such as lakesides, marshes, salt marshes, lawns, and damp fields, as well as moist meadows, forest openings, and along streams. It will also colonize disturbed sites such as ditches, clearcuts, and overgrazed pastures. Its North American range extends from the subarctic into Mexico, mostly at low to middle elevations.

Agrostis stolonifera has been confused with A. gigantea (see previous). It is considered to be Eurasian, but some northern salt marsh and lakeside populations may be native. Agrostis stolonifera is also similar to A. castellana (p. 639); it differs in having longer, acute to truncate ligules that are longer than wide, and in possessing extensive stolons. The names A. palustris Huds. and A. maritima Lam. have been applied to plants with longer stolons; all forms intergrade. A hybrid between A. stolonifera and Polypogon monspeliensis, xAgropogon lutosus (p. 668), has been found in the Flora region. It differs from A. stolonifera in having awned glumes and lemmas. Agrostis stolonifera readily hybridizes with A. vinealis (see below), the hybrids being somewhat intermediate between the two parents.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Agrostis exarata is common and widely distributed in western North America, usually growing in moist ground in open woodlands, river valleys, tidal marshes, and swamp and lake margins; it also grows in dry habitats such as grasslands and shrublands. It extends from Alaska into Mexico, and is also found in Kamchatka and the Kuril Islands. Eastern North American records probably reflect introductions. It readily colonizes roadsides and bare soil, and exhibits ecological and developmental flexibility. Agrostis exarata is recognized here as a single, variable species that includes what others have treated as distinct species or varieties. Cytotaxonomic study might clarify the basis of the observed variation. Agrostis exarata appears to be related to A. densiflora (see below).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 24, p. 641. FNA vol. 24, p. 651.
Parent taxa Poaceae > subfam. Pooideae > tribe Poeae > Agrostis Poaceae > subfam. Pooideae > tribe Poeae > Agrostis
Sibling taxa
A. anadyrensis, A. blasdalei, A. canina, A. capillaris, A. castellana, A. clavata, A. densiflora, A. elliottiana, A. exarata, A. gigantea, A. hallii, A. hendersonii, A. hooveri, A. howellii, A. hyemalis, A. idahoensis, A. mertensii, A. microphylla, A. nebulosa, A. oregonensis, A. pallens, A. perennans, A. rossiae, A. scabra, A. tolucensis, A. variabilis, A. vinealis
A. anadyrensis, A. blasdalei, A. canina, A. capillaris, A. castellana, A. clavata, A. densiflora, A. elliottiana, A. gigantea, A. hallii, A. hendersonii, A. hooveri, A. howellii, A. hyemalis, A. idahoensis, A. mertensii, A. microphylla, A. nebulosa, A. oregonensis, A. pallens, A. perennans, A. rossiae, A. scabra, A. stolonifera, A. tolucensis, A. variabilis, A. vinealis
Synonyms A. stolonifera var. palustris, A. stolonifera var. compacta, A. palustris, A. maritima, A. alba var. stolonifera, A. alba var. palustris, A. alba forma aristigera A. longiligula var. australis, A. longiligula, A. exarata var. purpurascens, A. exarata var. pacifica, A. exarata var. monolepis, A. exarata var. minor, A. exarata subsp. minor, A. ampla, A. alaskana
Name authority L Trin.
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