Your help is appreciated. We depend on donations to help keep this site free and up to date for you. Can you please help us?

Donate

Native Plant Trust: Go Botany Discover thousands of New England plants

Poa laxa — wavy blue grass

Copyright: various copyright holders. To reuse an image, please click it to see who you will need to contact.

Facts

Wavy blue grass is found on alpine plateaus, ravines and summits in the mountains of Maine, New Hampshire and Vermont. It is very rare in New England, where its habitat is uncommon and populations are somewhat separated from the heart of its range. The 10-25 cm (4-10 inch) tall stems are weak ("laxa" means "weak") and open, and this grass produces no rhizomes. If fruits in July and August. It is distinctive from all other alpine grasses (in Maine) by having floral scales without bristles (awns). Our subspecies is fernaldiana, named for the famous New England botanist, Merritt Lyndon Fernald (1873-1950).

Habitat

Alpine or subalpine zones, mountain summits and plateaus, talus and rocky slopes

New England distribution

Adapted from BONAP data

Found this plant? Take a photo and post a sighting.

North America distribution

Adapted from BONAP data

enlarge

Characteristics

Habitat
terrestrial
New England state
Vermont
Leaf blade width
1–3 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
4–6 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 sheath hair type
there are no hairs on the surface of the leaf sheath
Leaf ligule length
2.5–3.5 mm
Anther length
0.7–0.9 mm
Show all characteristics
  • Flowers

    Anther length
    0.7–0.9 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
    2–5
    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
    • 1
    • 3
    Glumes per spikelet
    2
    Inflorescence arrangement
    the spikelets are uniform
    Inflorescence axis orientation
    • the inflorescence axis bends downwards or hangs
    • the inflorescence axis is arched or curved outward
    • the inflorescence axis is straight
    Inflorescence branch length
    1–4 cm
    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
    1–3
    Inflorescence crowding
    • the panicle is somewhat to very congested (crowded), and the branches may not be clearly seen without close inspection
    • the panicle is somewhat to very spread out, with clearly-evident branches
    Inflorescence length
    20–80 mm
    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
    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 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
    2.6–4.2 mm
    Lower glume relative length
    • the lower glume is nearly as long, or as long as, the upper glume
    • the lower glume is one third to three quarters 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
    4–6 mm
    Spikelet number per node
    Up to 8
    Spikelet pedicel
    the spikelets have pedicels
    Spikelet position
    the spikelets emerge mainly from the upper halves of the inflorescence branches
    Spikelet shape
    the spikelets are oblong (rectangular, but 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
    2.8–3.4 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 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
    • the plant has large or prominent tufts of leaves at 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 texture
    the leaf blade is smooth, or it may have soft hairs
    Leaf blade width
    1–3 mm
    Leaf ligule length
    2.5–3.5 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 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 upright, or at less than a 45 degree angle out from the stem
  • Place

    Habitat
    terrestrial
    New England state
    Vermont
    Specific habitat
    • alpine or subalpine zones
    • mountain summits and plateaus
    • talus or rocky slopes
  • Stem, shoot, branch

    Hairs at nodes
    the stem nodes are hairless or they have very sparse hairs
    Plant height
    8–35 cm
    Stem hairs
    the stem is nearly to completely hairless
    Stem orientation
    the stems are upright
    Stem spacing
    the stems grow close together in compact clusters or tufts
    Stem thickness at base
    0.5–0.9 mm

Wetland status

Not classified

In New England

Distribution

Connecticut
absent
Maine
present
Massachusetts
absent
New Hampshire
present
Rhode Island
absent
Vermont
present

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

ssp. fernaldiana

Maine
extremely rare (S-rank: S1), endangered (code: E)
New Hampshire
extremely rare (S-rank: S1), endangered (code: E)
Vermont
extremely rare (S-rank: S1)

Subspecies and varieties

Our subspecies is Poa laxa Haenke ssp. fernaldiana (Nannf.) N. Hylander.

From Flora Novae Angliae dichotomous key

8.  Poa laxa Haenke ssp. fernaldiana (Nannf.) N. Hylander NC

wavy blue grass. ME, NH, VT. Alpine plateaus, ravines, and summits.

Native to North America?

Yes

Sometimes confused with

Poa glauca:
anthers mostly 1–2.2 mm long, ligules mostly 1.2-2 mm long, and branches of panicle moderately to densely scabrous on the angles (vs. P. laxa, with anthers 0.7–0.9 mm long, ligules 2.5–3.5 mm long, and branches of panicle smooth or sparsely scabrous on the angles).

Synonyms

  • Poa laxa Haenke ssp. fernaldiana (Nannf.) N. Hylander

Family

Poaceae

Genus

Poa