Agrostis stolonifera |
Agrostis gigantea |
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agrostide stolonifere, carpet bentgrass, creeping bent, creeping bentgrass, fiorin, redtop, spreading bent |
agrostide blanche, black bent, creeping bentgras, redtop, redtop bentgrass |
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Habit | Plants perennial; stoloniferous, stolons 5-100+ cm, rooting at the nodes, often forming a dense mat, without rhizomes. | Plants perennial; rhizomatous, rhizomes to 25 cm, not stoloniferous. |
Culms | (8)15-60 cm, erect from a geniculate base, sometimes rooting at the lower nodes, with (2)4-7 nodes. |
20-120 cm, erect, sometimes geniculate at the base, sometimes rooting at the lower nodes, with 4-7 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 sparsely scabridulous; ligules longer than wide, dorsal surfaces usually scabrous, sometimes smooth, apices rounded to truncate, erose to lacerate, basal ligules 1-4.5 mm, upper ligules 2-7 mm; blades 4-10 cm long, 3-8 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. |
8-25(30) cm long, less than 1/2 the length of the culm, (1.5)3-15 cm wide, erect, open, broadly ovate, exserted from the upper sheaths at maturity, lowest node with (1)3-8 branches; branches scabrous, spreading during and after anthesis, usually some branches spikelet-bearing to the base, lower branches 4-9 cm, usually with many shorter secondary branches resulting in crowding of the spikelets, spikelets restricted to the distal 1/2 of the branches and not crowded in shade plants; pedicels 0.3-3.4(4.2) mm. |
Spikelets | lanceolate, green and slightly to strongly suffused with purple. |
narrowly ovate to lanceolate, green and slightly to strongly suffused with purple. |
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, 1.7-3.2 mm, lanceolate, 1-veined, acute to apiculate; lower glumes scabrous on the distal 1/2 of the midvein; upper glumes scabridulous on the distal 1/2 of the midvein; callus hairs to 0.5 mm, sparse; lemmas 1.5-2.2 mm, opaque to translucent, smooth, 3-5-veined, veins usually obscure, sometimes prominent throughout or distally, often excurrent to 0.2 mm, apices usually acute, sometimes obtuse or truncate, usually unawned, rarely with a 0.4-1.5(3) mm straight awn arising from near the apices to near the base; paleas 0.7-1.4 mm, about Vi the length of the lemmas, veins visible; anthers 3, 1-1.4 mm. |
Caryopses | 0.9-1.3 mm; endosperm solid. |
1-1.5 mm; endosperm solid. |
2n | = 28, 35,42. |
= 42. |
Agrostis stolonifera |
Agrostis gigantea |
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Distribution |
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
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AK; AL; AR; AZ; CA; CO; CT; DC; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; LB; MB; NB; NS; NT; ON; PE; QC; SK; YT; Greenland
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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 gigantea grows in fields, roadsides, ditches, and other disturbed habitats, mostly at lower elevations. It is a serious agricultural weed, as well as a valuable soil stabilizer. In the Flora region, its range extends from the subarctic to Mexico; it is considered to be native to Eurasia. It is more heat tolerant than most species of Agrostis. Agrostis gigantea has been confused with A. stolonifera (see next), from which it differs in having rhizomes and a more open panicle. Agrostis stolonifera has elongated leafy stolons, mainly all above the surface, that root at the nodes, and the panicles are condensed and often less strongly pigmented than in A. gigantea. Its distribution tends to be more northern and coastal where ditches and pond margins are common habitats, and its stolons enable it to form loose mats. Agrostis gigantea is ecologically adapted to a more extreme climate—hot summers/cold winters and drought—than A. stolonifera. It is also similar to A. capillaris (p. 639) and A. castellana (p. 639); it differs from both in its longer ligules, from A. capillaris in its less open panicles with spikelets near the base of the branches, and from A. castellana in being more extensively rhizomatous. When Agrostis gigantea grows in damp hollows under trees it becomes more like A. stolonifera, particularly when the inflorescence is young, not expanded, and pale. If the rootstock is not collected, identification is a major problem. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 641. | FNA vol. 24, p. 641. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Poeae > Agrostis | Poaceae > subfam. Pooideae > tribe Poeae > Agrostis |
Sibling taxa | ||
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. stolonifera var. major, A. gigantea var. ramosa, A. gigantea var. dispar, A. alba var. major |
Name authority | L | Roth |
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