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- Dichotomous Key
- Poaceae
- Poaceae Group 4
- Poa
- Poa nemoralis
Poa nemoralis — wood blue grass
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Facts
Wood blue grass was introduced from Eurasia and is now common in mixed woodlands of the northeastern United States and is spreading to the west.
Habitat
Anthropogenic (man-made or disturbed habitats), floodplain (river or stream floodplains), forests, shores of rivers or lakes
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.
Found this plant? Take a photo and post a sighting.
Characteristics
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf blade width
- 0.8–3 mm
- Inflorescence branches
- the flowers are attached to branches rather than to the main axis of the inflorescence
- Spikelet length
- 3–8 mm
- Glume relative length
- neither glume is quite as long as all of the florets
- Awn on glume
-
- the glume has an awn
- the glume has no awn
- One or more florets
- there is more than one floret per spikelet
- Lemma awn length
- 0 mm
- Leaf sheath hair type
- there are no hairs on the surface of the leaf sheath
- Leaf ligule length
- 0.2–1 mm
- Anther length
- 0.8–1.9 mm
-
Flowers
- Anther length
- 0.8–1.9 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
- 1–5
- 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
- 3
- Glumes per spikelet
- 2
- 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 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
- 2–5
- Inflorescence crowding
- the panicle is somewhat to very spread out, with clearly-evident branches
- Inflorescence length
- 70–200 mm
- Inflorescence length to width ratio
- 2.5–4
- 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
- 18–80 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 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 covered with small wart-like projections
- 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 narrow point (it may or may not also have an awn or teeth at the tip)
- Lemma vein number
-
- 3
- 5
- Lower glume length
- 2.2–3 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 length
- 2.4–4 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 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
- 3–8 mm
- Spikelet number per node
- 0
- Spikelet pedicel
- the spikelets have pedicels
- Spikelet pedicel length
- 0.5–6 mm
- Spikelet position
- the spikelets emerge mainly from the upper 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
- 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
- 2.3–3.3 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 more than two years
- 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 base
- the leaf blade is rounded in to a narrower base, or the blade cuts in abruptly to the narrower base
- 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
- 5–12 cm
- Leaf blade texture
- the leaf blade is rough and sandpapery
- Leaf blade width
- 0.8–3 mm
- Leaf ligule length
- 0.2–1 mm
- Leaf ligule type
- the leaf ligule is in the form of a membrane with fine hairs
- 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 color and persistence
- the leaf sheathes are off-white to light-brown and mostly persist in older leaves
- 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
- Orientation of topmost leaf
-
- the flag leaf is held outward at more than a 45 degree angle from the stem, or it curves downwards from the horizontal
- the flag leaf is held upright, or at less than a 45 degree angle out from the stem
-
Place
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- forests
- man-made or disturbed habitats
- river or stream floodplains
- shores of rivers or lakes
-
Stem, shoot, branch
- Hairs at nodes
- the stem nodes are hairless or they have very sparse hairs
- Plant height
- 30–80 cm
- Roots at lower stem nodes
- no
- Stem hairs
- the stem is nearly to completely hairless
- Stem node number
- 3–5
- Stem orientation
- the stems are upright
- Stem spacing
- the stems grow close together in compact clusters or tufts
Wetland status
Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)
In New England
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
- unranked (S-rank: SNR)
- Vermont
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
9. Poa nemoralis L. E
wood blue grass. CT, MA, ME, NH, RI, VT. Riparian forests, mesic to dry-mesic upland forests, roadsides, areas of habitation, rarely on rivershore ledges. Herbarium collections are sometimes confused with Poa glauca (see discussion under that species).
Native to North America?
No
Sometimes confused with
- Poa palustris:
- ligules mostly 1.5-6 mm long and base of lemma with abundant soft, tangled hairs (vs. P. nemoralis, with ligules mostly 0.2-0.7 mm long and base of lemma with sparse soft, tangled hairs).