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- Agrostis exarata
Agrostis exarata — spike 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
The native range of spike bentgrass is western North America, where it occupies a wide range of habitats and altitudes. It is known in New England only from Vermont, where it is introduced.
Habitat
Anthropogenic (man-made or disturbed habitats), forest edges, forests
Characteristics
- Habitat
- terrestrial
- New England state
- Vermont
- Leaf blade width
- 2–7 mm
- Inflorescence branches
-
- the flowers are attached to branches rather than to the main axis of the inflorescence
- there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious
- Spikelet length
- 1.5–3.5 mm
- Glume relative length
- one or both glumes are as long or longer than all of the florets
- Awn on glume
-
- the glume has an awn
- the glume has no awn
- One or more florets
- there is one floret per spikelet
- Lemma awn length
- 0–3.5 mm
- Leaf sheath hair type
- there are no hairs on the surface of the leaf sheath
- Leaf ligule length
- 1–11.2 mm
- Anther length
- 0.3–0.6 mm
-
Flowers
- Anther length
- 0.3–0.6 mm
- Anther number
- 3
- Awn on glume
-
- the glume has an awn
- 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
- Up to 1 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 veins
-
- 1
- 3
- Glumes per spikelet
- 2
- Inflorescence arrangement
- the spikelets are uniform
- Inflorescence axis orientation
- the inflorescence axis is straight
- Inflorescence branch length
- 1–4 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
- there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious
- Inflorescence crowding
- the panicle is somewhat to very congested (crowded), and the branches may not be clearly seen without close inspection
- Inflorescence length
- 30–300 mm
- Inflorescence length to width ratio
- 6–7.5
- 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
- 5–40 mm
- Inforescence position
- the spikelets are mainly carried at the end of the stem
- Lemma awn base
- the awn is attached at the upper half of the lemma
- Lemma awn coiled
- the lemma awn is straight or twisted, but not coiled one half turn
- Lemma awn length
- 0–3.5 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
- the awn of the lemma on dried or older plants is curved or bent outwards
- Lemma base hair length
- Up to 0.3 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 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)
- the lemma tip is split into two or more points
- Lemma tip shape
- 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
- 5
- Lemma vein orientation
- the veins on the lemma stay roughly parallel throughout
- Lower glume length
- 1.5–3.5 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
- 0–0.5 mm
- Palea relative length
- palea is less than one half as long as lemma or absent
- Reproductive system
- all the flowers on the plant have both carpels and stamens (synoecious)
- 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
- 1.5–3.5 mm
- Spikelet number per node
- 0
- 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
- 1.5–3.5 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
- 0.9–1.2 mm
-
Growth form
- Horizontal rooting stem
- no
- Lifespan
- the plant lives more than two years
- Rhizomes
- no
-
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 hairs
- the leaf blade is hairless, but it may have tiny prickles that give it a sand-papery feel
- Leaf blade length
- 4–15 cm
- Leaf blade width
- 2–7 mm
- Leaf ligule length
- 1–11.2 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
- New England state
- Vermont
- Specific habitat
-
- edges of forests
- forests
- man-made or disturbed habitats
-
Stem, shoot, branch
- Plant height
- 8–100 cm
- Roots at lower stem nodes
-
- no
- yes
- Stem node number
- 2–8
- Stem orientation
-
- the stems are upright
- the stems trail at the base, but turn upwards at the tips
- Stem spacing
-
- the stems grow close together in compact clusters or tufts
- the stems grow singly or a few together (they may form diffuse colonies)
Wetland status
Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)
New England distribution and conservation status
Distribution
- Connecticut
- absent
- Maine
- absent
- Massachusetts
- absent
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- present
Conservation status
None
Native to North America?
Yes and no (some introduced)
Sometimes confused with
- Agrostis stolonifera:
- paleas 0.7-1.4 mm long, anthers 0.9-1.4 mm long, and plants with stolons (vs. A. exarata, with paleas absent or up to 0.5 mm, anthers 0.3-0.6 mm long, and plants lacking stolons).
Synonyms
- Agrostis exarata Trin. var. monolepis (Torrey) A.S. Hitchc.
Family
Genus
From the dichotomous key of Flora Novae Angliae
4. Agrostis exarata Trin. E
spike bentgrass. Agrostis exarata Trin. var. monolepis (Torrey) A.S. Hitchc. • VT. Forest clearings, edges of gravel roads.