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- Poa chapmaniana
Poa chapmaniana — Chapman's blue grass
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Facts
Chapman's blue grass is uncommon in New England, having been collected only in Massachusetts, where it is considered non-native. It is native to the prairies, south to the east coast. It looks similar to its more common cousin, Poa annua (annual blue grass), but the callus has webbed hairs and the florets only have one short anther. The species is named for Alvan Wentworth Chapman (1809-1899), a physician and botanist who published one of the first comprehensive floras of the southeastern United States.
Habitat
Anthropogenic (man-made or disturbed habitats), meadows and fields
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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Characteristics
- Habitat
- terrestrial
- New England state
- Massachusetts
- Leaf blade width
- 0.6–2.8 mm
- Inflorescence branches
- the flowers are attached to branches rather than to the main axis of the inflorescence
- Spikelet length
- 2–4.5 mm
- Glume relative length
- neither glume is quite as long as all of the florets
- Awn on glume
- the glume has no awn
- One or more florets
- there is more than one floret per spikelet
- Lemma awn length
- 0 mm
- Leaf ligule length
- 0.7–5 mm
- Anther length
- 0.1–0.2 mm
-
Flowers
- Anther length
- 0.1–0.2 mm
- Anther number
- 1
- Awn on glume
- the glume has no awn
- Bristles below spikelets
- no
- Floret lower bract texture
- the lemma is thin and flexible
- Floret number
- 1–6
- 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
- the glume keels are smooth and hairless
- Glume relative length
- neither glume is quite as long as all of the florets
- Glume shape
- the glume is V-shaped in cross-section
- Glume veins
-
- 1
- 3
- Inflorescence arrangement
- the spikelets are uniform
- Inflorescence axis orientation
-
- the inflorescence axis is arched or curved outward
- the inflorescence axis is straight
- Inflorescence branch roughness
- the inflorescence branches are smooth or only slightly 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
- 1–7
- Inflorescence crowding
- the panicle is somewhat to very congested (crowded), and the branches may not be clearly seen without close inspection
- Inflorescence length
- 20–96 mm
- Inflorescence length to width ratio
- 1.9–2
- Inflorescence type (general)
- 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
- 10–50 mm
- Inforescence position
- the spikelets are mainly carried at the end of the stem
- Lemma awn base
- NA
- Lemma awn coiled
- NA
- Lemma awn length
- 0 mm
- Lemma awn number
- the lemma has no awn
- Lemma awn orientation
- NA
- Lemma base hairs
- the lemma has hairs at the base
- Lemma cross-section
- the lemma is V-shaped if you cut across the midpoint
- Lemma hairs
-
- the lemma has fine hairs between the veins
- 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 has fine hairs on it
- 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 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
- Lower glume length
- 1.5–3 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 more than one floret per spikelet
- 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 tip
- there is an 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
- 2–4.5 mm
- Spikelet number per node
- Up to 0
- Spikelet pedicel
- the spikelets have pedicels
- Spikelet pedicel length
- 0.3–4 mm
- Spikelet position
- the spikelets emerge from both the upper and lower halves of the inflorescence branches
- Spikelet shape
-
- the spikelets are oblong (rectangular, but with rounded ends) in profile
- the spikelets are ovate (egg-shaped, widest below the middle with rounded ends) in profile
- Spikelet width
- 1.5–2.2 mm
- 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
- 2–4 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
-
Growth form
- Horizontal rooting stem
- no
- Lifespan
- the plant lives only a single year or less
- Rhizomes
- no
- Roots
- there are only slender roots on the plant
-
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 clearly folded or rolled inwards
- 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
- 2–8 cm
- Leaf blade texture
- the leaf blade is smooth, or it may have soft hairs
- Leaf blade width
- 0.6–2.8 mm
- Leaf ligule length
- 0.7–5 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 fused together and form a closed tube except (possibly) at the very top
- the margins of the leaf sheath are overlapping and not fused together except in the basal half (or less)
- Orientation of topmost leaf
- the flag leaf is held upright, or at less than a 45 degree angle out from the stem
-
Place
- Habitat
- terrestrial
- New England state
- Massachusetts
- Specific habitat
-
- man-made or disturbed habitats
- meadows or fields
-
Stem, shoot, branch
- Hairs at nodes
- the stem nodes are hairless or they have very sparse hairs
- Plant height
- 5–40 cm
- Stem hairs
- the stem is nearly to completely hairless
- Stem node number
- 2–4
- 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
- Stem thickness at base
- 0.3–0.7 mm
Wetland status
Occurs only in non-wetlands. (Wetland indicator code: UPL)
In New England
Distribution
- Connecticut
- absent
- Maine
- absent
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- absent
- Vermont
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
4. Poa chapmaniana Scribn. E
Chapman’s blue grass. MA. Fields, lawns, areas of cultivation, disturbed soil.
Native to North America?
Yes and no (some introduced)
Sometimes confused with
- Poa annua:
- callus of the lemma without arachnoid hairs, reproductive stems mostly decumbent to ascending, sometimes even rooting at the lower nodes, and anthers mostly 0.8–1 mm long (vs. P. chapmaniana, with callus of the lemma with arachnoid hairs, reproductive stems strongly ascending to erect, and anthers 0.1–0.2 mm long).