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- Poaceae Group 5
- Leymus
- Leymus mollis
Leymus mollis — American lyme grass
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Facts
American lyme grass is a common dune grass from Atlantic and Pacific coast beaches. Its bluish-green foliage and stout spikelets that contain more than one floret distinguish it from the common beach grass, Ammophila breviligulata, with which it often co-occurs. Dune grasses possess special adaptations that allow them to tolerate and grow faster in response to repeated burial by sand. As such, they are critical for stabilizing dunes against erosion.
Habitat
Coastal beaches (sea beaches)
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
- New England state
-
- Maine
- Massachusetts
- New Hampshire
- Leaf blade width
- 3–15 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
- 15–34 mm
- Glume relative length
-
- neither glume is quite as long as all of the florets
- 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 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
- 0.2–2.5 mm
- Anther length
- 4–9 mm
-
Flowers
- Anther length
- 4–9 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
- 3–6
- 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
- one or both glumes are as long or longer than all of the florets
- Glume shape
-
- the glume is V-shaped in cross-section
- the glume is flat or curved in cross-section
- Glume veins
-
- 3
- 5
- Glumes per spikelet
- 2
- Inflorescence axis hairs
- the inflorescence axis is hairy but not rough or sand-papery feeling
- Inflorescence axis orientation
-
- the inflorescence axis is arched or curved outward
- the inflorescence axis is straight
- Inflorescence branch length
- 0 cm
- Inflorescence branch roughness
- NA
- 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 branches coming off the lowest stem node
- 0
- Inflorescence crowding
- NA
- Inflorescence length
- 120–340 mm
- Inflorescence length to width ratio
- 12–17
- Inflorescence type (general)
- the inflorescence is a spike, or is spike-like, lacking obvious branches
- Inflorescence type (specific)
- the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
- Inflorescence width
- 10–20 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 cross-section
- the lemma is V-shaped if you cut across the midpoint
- Lemma hairs
- the lemma has fine hairs 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
- 5
- Lemma vein orientation
- the veins on the lemma stay roughly parallel throughout
- Lower glume length
- 24–13 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
- 10–13 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 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
- 15–34 mm
- Spikelet number per node
- Up to 3
- Spikelet pedicel
- the spikelets do not have pedicels
- Spikelet pedicel length
- 0 mm
- Spikelet position
- NA
- Spikelet shape
- the spikelets are elliptic (widest in the middle, tapering to the ends) in profile
- Spikelet width
- 5–7 mm
- Spikelets per panicle branch
- 0
- 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
- 13–34 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 above the middle
- the upper glume is widest at or below the middle
-
Fruits or seeds
- Groove on seed
- the caryopsis has a groove running most of its length
-
Growth form
- 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 large or prominent tufts of leaves at the base of the flowering stem
- Leaf auricles
- the leaves have auricles
- Leaf basal lobe hairy
- the lobes at the base of the leaf blades are hairless
- Leaf blade base
- the leaf is tapered gradually to the base
- 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
- 10–94 cm
- Leaf blade texture
- the leaf blade is rough and sandpapery
- Leaf blade width
- 3–15 mm
- Leaf ligule length
- 0.2–2.5 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 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
-
- Maine
- Massachusetts
- New Hampshire
- Specific habitat
- sea beaches
-
Stem, shoot, branch
- Plant height
- 50–170 cm
- Stem hairs
- the stem has hairs on it
- Stem node number
- 3–4
- Stem orientation
- the stems are upright
- 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)
- Stem thickness at base
- 3–6 mm
Wetland status
Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)
In New England
Distribution
- Connecticut
- absent
- Maine
- present
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- absent
- Vermont
- absent
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Maine
- unranked (S-rank: SNR)
ssp. mollis
- Massachusetts
- extremely rare (S-rank: S1), endangered (code: E)
- New Hampshire
- extremely rare (S-rank: S1), endangered (code: E)
Subspecies and varieties
Our variety is Leymus mollis (Trin.) Hara var. mollis.
From Flora Novae Angliae dichotomous key
1. Leymus mollis (Trin.) Hara var. mollis N
American lyme grass. Elymus arenarius L. var. villosus E. Mey.; E. capitatus Scrib.; E. mollis Trin.; Leymus arenarius (L.) Hochst. ssp. mollis (Trin.) Tzvelev • MA, ME, NH. Atlantic coast beaches.
Native to North America?
Yes and no (some introduced)
Sometimes confused with
- Ammophila breviligulata:
- inflorescence a highly congested panicle, spikelets with only 1 floret, and lemmas not pubescent over the abaxial surface (vs. L. mollis, with the inflorescence a spike and spikelets with 3-6 florets, and lemmas pubescent over the abaxial surface).
Synonyms
- Elymus arenarius L. var. villosus E. Mey.
- Elymus capitatus Scrib.
- Elymus mollis Trin.
- Leymus arenarius (L.) Hochst. ssp. mollis (Trin.) Tzvelev