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- Grass-like plants
- True grasses
- Agrostis gigantea
Agrostis gigantea — redtop bentgrass
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New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
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Facts
Redtop bentgrass is used in lawns and golf courses in many parts of the world, and may be a serious agricultural weed in some places. It is also planted for erosion control along riparian zones and wetlands. It is found throughout New England.
Habitat
Anthropogenic (man-made or disturbed habitats), meadows and fields, shores of rivers or lakes
Characteristics
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf blade width
- 3–9 mm
- Inflorescence branches
- the flowers are attached to branches rather than to the main axis of the inflorescence
- Spikelet length
- 2–3.5 mm
- Glume relative length
- one or both glumes are as long or longer than all of the florets
- Awn on glume
- the glume has no awn
- One or more florets
- there is one floret per spikelet
- Lemma awn length
- 0–3 mm
- Leaf sheath hair type
- there are no hairs on the surface of the leaf sheath
- Leaf ligule length
- 1–7 mm
- Anther length
- 1–1.4 mm
-
Flowers
- Anther length
- 1–1.4 mm
- Anther number
- 3
- Awn on glume
- the glume has no awn
- Bristles below spikelets
- no
- Floret lower bract texture
- the lemma is thin and flexible
- Floret number
- 1
- Floret types within spikelet
- all the florets within a spikelet are similar
- Glume awn length
- 0 mm
- Glume keel
- the glume keels are rough or hairy
- Glume relative length
- one or both glumes are as long or longer than all of the florets
- Glume shape
- the glume is V-shaped in cross-section
- Glume veins
- 1
- Glumes per spikelet
- 2
- Inflorescence arrangement
- the spikelets are uniform
- Inflorescence axis orientation
- the inflorescence axis is straight
- Inflorescence branch length
- 4–9 cm
- Inflorescence branch roughness
- the inflorescence branches are somewhat to very rough
- Inflorescence branches
- the flowers are attached to branches rather than to the main axis of the inflorescence
- Inflorescence branches coming off the lowest stem node
- 1–8
- Inflorescence crowding
- the panicle is somewhat to very spread out, with clearly-evident branches
- Inflorescence length
- 80–300 mm
- Inflorescence length to width ratio
- 2–5.3
- Inflorescence type (general)
-
- the inflorescence is a spike, or is spike-like, lacking obvious branches
- the spikelets are borne on stalks or on branches
- Inflorescence type (specific)
- the inflorescence is branched, and the branches do NOT both grow from the same side of the plant AND look like spikes
- Inflorescence width
- 15–150 mm
- Inforescence position
- the spikelets are mainly carried at the end of the stem
- Lemma awn coiled
- the lemma awn is straight or twisted, but not coiled one half turn
- Lemma awn length
- 0–3 mm
- Lemma awn number
-
- the lemma has no awn
- the lemma has one awn on it
- Lemma awn orientation
- the awn of the lemma is straight
- Lemma base hair length
- Up to 0.5 mm
- Lemma base hairs
- the lemma has hairs at the base
- Lemma cross-section
- the lemma is flat or rounded if you cut across the midpoint
- Lemma hairs
- the lemma is hairless between the veins
- Lemma keel hairs
- the keel of the lemma is rough, or has fine hairs
- Lemma marginal vein hairs
- the marginal vein of the lemma is hairless
- Lemma surface
- the surface of the lemma is relatively smooth (not counting any longitudinal veins or hairs)
- Lemma tip
- the lemma tip is a simple point, with or without an awn (long narrow extension ending in a point)
- Lemma tip shape
-
- the lemma tip is rounded off or truncate (ends abruptly in a more or less straight line as though cut off); it may or may not also have an awn or teeth at the tip
- the lemma tip tapers to a broad point (it may or may not also have an awn or teeth at the tip)
- the lemma tip tapers to a narrow point (it may or may not also have an awn or teeth at the tip)
- Lemma vein number
-
- 3
- 5
- Lemma vein orientation
- the veins on the lemma stay roughly parallel throughout
- Lower glume length
- 1.7–3.2 mm
- Lower glume relative length
- the lower glume is nearly as long, or as long as, the upper glume
- One or more florets
- there is one floret per spikelet
- Palea length
- 0.7–1.4 mm
- Palea relative length
- palea is one half to fully as long as lemma
- Reproductive system
- all the flowers on the plant have both carpels and stamens (synoecious)
- Spikelet axis length
- 0 mm
- Spikelet axis tip
- there is no extension of the spikelet axis beyond the tip of the spikelet
- Spikelet disintegration
- the spikelet breaks off above the glumes, so that after the florets fall off, the glumes remain
- Spikelet length
- 2–3.5 mm
- Spikelet number per node
- 0
- Spikelet pedicel
- the spikelets have pedicels
- Spikelet pedicel length
- 0.3–4.2 mm
- Spikelet position
- the spikelets emerge from both the upper and lower halves of the inflorescence branches
- Spikelet shape
-
- the spikelets are lanceolate (lance-shaped, widest below the middle and tapering narrowly to the ends) in profile
- the spikelets are ovate (egg-shaped, widest below the middle with rounded ends) in profile
- Spikelets spiny
- the spikelets do not appear spiny
- Tip of glume
- the tip of the glume is not divided (though it may have an awn on it)
- Upper glume length
- 1.7–3.2 mm
- Upper glume relative length
- the upper glume is more than one half as long as the lowest lemma
- Upper glume shape
- the upper glume is widest at or below the middle
-
Fruits or seeds
- Seed length
- 1–1.5 mm
-
Growth form
- Horizontal rooting stem
- no
- Lifespan
- the plant lives more than two years
- Rhizomes
- yes
- Roots
- the plant has rhizomes (horizontal underground stem with roots growing from it)
-
Leaves
- Basal leaves
- the plant has few or no leaves coming from the base of the flowering stem
- Leaf auricles
- the leaves do not have auricles
- Leaf basal lobe hairy
- NA
- Leaf blade cross-section
- the leaf blade is more or less flat in cross-section, or slightly folded or rolled inwards
- Leaf blade hairs
- the leaf blade is hairless, but it may have tiny prickles that give it a sand-papery feel
- Leaf blade length
- 4–10 cm
- Leaf blade texture
- the leaf blade is rough and sandpapery
- Leaf blade width
- 3–9 mm
- Leaf ligule length
- 1–7 mm
- Leaf ligule type
- the leaf ligule is in the form of a membrane
- Leaf margin glands
- there are no glands along the edges of the leaf blade
- Leaf sheath closed around stem
- the margins of the leaf sheath are overlapping and not fused together except in the basal half (or less)
- Leaf sheath hair type
- there are no hairs on the surface of the leaf sheath
- Leaf sheath hairs
- there are no hairs on the surface of the leaf sheath
-
Place
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- man-made or disturbed habitats
- meadows or fields
- shores of rivers or lakes
-
Stem, shoot, branch
- Hairs at nodes
- the stem nodes are hairless or they have very sparse hairs
- Plant height
- 20–120 cm
- Roots at lower stem nodes
-
- no
- yes
- Stem hairs
- the stem is nearly to completely hairless
- Stem node number
- 4–7
- Stem orientation
- the stems are upright
- Stem spacing
- the stems grow close together in compact clusters or tufts
Wetland status
Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)
New England distribution and conservation status
Distribution
- Connecticut
- present
- Maine
- present
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- present
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- not applicable (S-rank: SNA)
Native to North America?
No
Sometimes confused with
- Agrostis capillaris:
- ligules 0.5-2 mm long and panicle branches bearing flowers only in distal half (vs. A. gigantea, with ligules 2-6 mm long and branches of panicle bearing flowers in distal and proximal halves).
- Agrostis stolonifera:
- stems decumbent and inflorescence yellow-brown with ascending branches during flowering (vs. stems upright at base and inflorescence usually red-purple with spreading branches during flowering).
Synonyms
- Agrostis alba, misapplied
- Agrostis nigra With.
- Agrostis stolonifera ssp. gigantea (Roth) Schuebl. & Martens
- Agrostis stolonifera var. major (Gaudin) Farw.
Family
Genus
From the dichotomous key of Flora Novae Angliae
5. Agrostis gigantea Roth E
redtop bentgrass. Agrostis alba, auct. non L.; A. nigra With.; A. stolonifera L. ssp. gigantea (Roth) Schuebl. & Martens; A. stolonifera L. var. major (Gaudin) Farw. • CT, MA, ME, NH, RI, VT; throughout. Fields, meadows, shorelines, roadsides.