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Species
Agrostis gigantea Roth var. dispar (Michx.) Philipson
IUCN
NCBI
EOL Text
More info for the term: cool-season
Redtop is an introduced, perennial, rhizomatous, cool-season,
sod-forming grass with erect, stout, stems growing 2 to 4 feet (0.6-1.2
m) tall. The panicle is 4 to 8 inches (10-20 cm) long and notably
suffused with purplish-red. Lemmas are rarely awned [22,29]. Rhizomes
are less than 10 inches (25 cm) long [28] and are generally shallow
[27]. Rhizomes have been reported to occur to a depth of 6 inches (15
cm) [18]. Redtop apparently intergrades with creeping bentgrass; redtop
has mostly erect culms and rhizomes, and creeping bentgrass has mostly
decumbent, stoloniferous culms.
Moist ground, rough grasslands, as a field weed. Anhui, Gansu, Hebei, Heilongjiang, Henan, Hubei, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xinjiang, Xizang, Yunnan, Zhejiang [Afghanistan, NW India, Japan, Korea, Mongolia, Nepal, Pakistan, Russia; N Africa, SW Asia, Europe].
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200024787 |
Canada
Rounded National Status Rank: NNA - Not Applicable
United States
Rounded National Status Rank: NNA - Not Applicable
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Rights holder/Author | NatureServe |
Source | http://explorer.natureserve.org/servlet/NatureServe?searchName=Agrostis+gigantea |
Perennials, Terrestrial, not aquatic, Rhizomes present, Rhizome elongate, creeping, stems distant, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems with inflorescence 1-2 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly basal, below middle of stem, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Infloresce nce an open panicle, openly paniculate, branches spreading, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence branches more than 10 to numerous, Lower panicle branches whorled, Flowers bisexual, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets disarticulating beneath or between the florets, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes 1 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma 3 nerved, Lemma 5-7 nerved, Lemma glabrous, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma margins thin, lying flat, Lemma strai ght, Palea present, well developed, Palea membranous, hyaline, Palea shorter than lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.
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Rights holder/Author | Compiled from several sources by Dr. David Bogler, Missouri Botanical Garden in collaboration with the USDA NRCS NPDC |
Source | http://plants.usda.gov/java/profile?symbol=AGGI2 |
Because of its tiny seed, redtop should have a firm, well-prepared seedbed. It may be sown in early spring or late summer. Seeding depth is 1/4 inch. Redtop is seldom seeded alone, except for temporary cover. Rates of seeding will vary depending upon purpose, and whether seeded alone or in mixtures. In mixtures, rates of 1 to 2 pounds per acre are generally used. For pure stands, seeding rates are from 4 to 5 pounds per acre. The higher rates are used for temporary critical area stabilization. Redtop grows rapidly after seeding and excessive seeding rates are not recommended, particularly in mixtures. When used for erosion control on critical areas, fertilizing is essential to give rapid cover.
Rounded Global Status Rank: G4 - Apparently Secure
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Rights holder/Author | NatureServe |
Source | http://explorer.natureserve.org/servlet/NatureServe?searchName=Agrostis+gigantea |
The currently accepted scientific name for redtop is Agrostis gigantea
Roth (Poaceae) [22,28,33,34].
There is considerable taxonomic confusion concerning this species. In
the literature, the most commonly used scientific name for redtop is A.
alba L. However, Linnaeus based his A. alba on a Poa species; the A.
alba in the literature is not the A. alba of Linnaeus [8]. In order to
escape this confusion, some authors have dropped the name A. alba but
have not reached a consensus on a new name. Redtop is often regarded
merely as the nonstoloniferous, mostly rhizomatous variety of the
morphologically variable creeping bentgrass (A. stolonifera) [23,42].
And conversely, creeping bentgrass is sometimes considered a variety of
A. alba [30,36]. Most literature referring to either A. alba or A.
stolonifera does not distinguish between the two species, and it is
generally impossible to determine which species the literature is
referring to. This writeup summarizes literature that refers to A.
gigantea, A. alba, and A. stolonifera var. major.
Rhizomatous perennial without stolons; culms 40-120(-150) cm high, erect or geniculately ascending, rooting and branching from the lower nodes, smooth. Leaf-blades 5-20 cm long, 2-8 mm wide, flat, scabrid; ligule 1.5-6 mm long, blunt. Panicle oblong to ovate, 8-25 cm long, loose and open, the branches clustered, spreading, divided above the naked base; inflated tip of pedicel scabrid. Spikelets 2-3 mm long, breaking up at maturity above the persistent glumes; glumes acute, awnless, rough on the keel; lemma 1.5-2.5 mm long, very blunt, usually awnless, rarely with a short awn from near the tip; palea half to two-thirds the length of the lemma; anthers 1-1.5 mm long.
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=200024787 |
In Great Britain and/or Ireland:
Foodplant / parasite
colony of Dreschler dematiaceous anamorph of Drechslera fugax parasitises Agrostis gigantea
Foodplant / gall
stroma of Epichlo causes gall of stem of Agrostis gigantea
Remarks: season: fertile in 8
Other: uncertain
Foodplant / spot causer
colony of Mastigosporium anamorph of Mastigosporium rubricosum causes spots on live leaf of Agrostis gigantea