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- Poaceae Group 5
- Elymus
- Elymus trachycaulus
Elymus trachycaulus — wheatgrass
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Facts
Slender wild-rye is a widespread native of gravelly and ledgy river shores, cliffs and talus slopes, as well as open areas near the coast, and a range of wetlands. There are two subspecies recognized in New England. This versatile plant grows from Greenland to Mexico, and is introduced to Asia. Its forms are quite plastic -- forest-dwelling plants flower later and are more slender and tall than grassland-inhabiting forms. Its upright spikelets are tightly arrayed in a zig-zig up a long flowering stem.
Habitat
Bogs, cliffs, balds, or ledges, fens, forests, meadows and fields, ridges or ledges, shores of rivers or lakes, talus and rocky slopes, woodlands
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
- 2–8 mm
- Inflorescence branches
- there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious
- Spikelet length
- 9–20 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 an awn
- the glume has no awn
- One or more florets
- there is more than one floret per spikelet
- Lemma awn length
- 0–24 mm
- Leaf sheath hair type
-
- there are hairs on the surface of the leaf sheath, but the hairs do not have blisters at their bases
- there are no hairs on the surface of the leaf sheath
- Leaf ligule length
- 0.2–0.8 mm
- Anther length
- 0.8–3 mm
-
Flowers
- Anther length
- 0.8–3 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
- 3–8
- Floret types within spikelet
- there are at least two distinct forms of florets within one spikelet
- Glume awn length
- 0–11 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 veins
-
- 3
- 5
- 7 or more
- Glumes per spikelet
- 2
- Inflorescence arrangement
- the spikelets are uniform
- Inflorescence axis hairs
-
- the inflorescence axis is rough and feels like sand-paper
- the inflorescence axis is smooth and has no hairs
- Inflorescence axis orientation
- the inflorescence axis is straight
- Inflorescence branch length
- 0 cm
- Inflorescence branch roughness
- NA
- Inflorescence branches
- 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
- 40–250 mm
- Inflorescence length to width ratio
- 20–31.3
- 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
- 2–8 mm
- Inforescence position
- the spikelets are mainly carried at the end of the stem
- Lemma awn base
- the awn is attached right at the tip of the lemma
- Lemma awn coiled
- the lemma awn is straight or twisted, but not coiled one half turn
- Lemma awn length
- 0–24 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 hairs
- the lemma is hairless between the veins
- Lemma keel hairs
-
- NA
- the keel of the lemma is hairless
- the keel of the lemma is rough, or has fine hairs
- Lemma marginal vein hairs
- the marginal vein of the lemma is hairless
- 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
- 7 or more
- Lemma vein orientation
- the veins on the lemma stay roughly parallel throughout
- Lower glume length
- 5–17 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
- 7–9 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
- 9–20 mm
- Spikelet number per node
- At least 1
- 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
- the spikelets are oblong (rectangular, but with rounded ends) in profile
- Spikelet width
- 3–6 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
- 5–17 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
- Horizontal rooting stem
- no
- Lifespan
- the plant lives more than two years
- Rhizomes
-
- no
- yes
- Roots
-
- the plant has rhizomes (horizontal underground stem with roots growing from it)
- 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
- the leaves have auricles
- 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
- the leaf blade is hairy
- Leaf blade length
- Up to 20 cm
- Leaf blade texture
- the leaf blade is smooth, or it may have soft hairs
- Leaf blade width
- 2–8 mm
- Leaf ligule length
- 0.2–0.8 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 hairs on the surface of the leaf sheath, but the hairs do not have blisters at their bases
- there are no hairs on the surface of the leaf sheath
- Leaf sheath hairs
-
- there are hairs on the surface of the leaf sheath
- 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
-
- bogs
- cliffs, balds, or ledges
- fens
- forests
- meadows or fields
- ridges or ledges
- shores of rivers or lakes
- talus or rocky slopes
- woodlands
-
Stem, shoot, branch
- Hairs at nodes
-
- the stem nodes are hairless or they have very sparse hairs
- the stem nodes have hairs that stand out at a shallow angle, or they curve downwards
- Plant height
- 30–150 cm
- Stem hairs
-
- the stem has hairs on it
- 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
- the stems grow singly or a few together (they may form diffuse colonies)
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.
- Connecticut
- unrankable (S-rank: SU)
- Vermont
- uncommon (S-rank: S3)
ssp. glaucus
- Massachusetts
- unranked (S-rank: SNR)
- New Hampshire
- unrankable (S-rank: SU), Ind (code: Ind)
ssp. subsecundus
- Connecticut
- fairly widespread (S-rank: S4)
ssp. trachycaulus
- Connecticut
- unrankable (S-rank: SU)
- Massachusetts
- unranked (S-rank: SNR)
- New Hampshire
- unrankable (S-rank: SU), Ind (code: Ind)
Subspecies and varieties
Subspecies glaucus is known from CT, MA, ME, NH, VT. Subspecies trachycaulus is known from CT, MA, ME, NH, RI, VT. Elymus subsecundus (synonym: E. trachycaulus var. unilateralis (Cassidy) Beetle) was reported from New England based on specimens with evident lemmas awns. These plants are, in fact, intermediate between E. trachycaulus and E. subsecundus and have been referred to by the epithet “ glaucus” by Fernald (1950b). Jozwik (1966) suggested that such plants with intermediate awn length and sometimes divergent awns are often hybrids between E. trachycaulus and E. subsecundus. If this hypothesis is confirmed, ssp. glaucus should be recognized at the specific level to ensure its name does not imply an incorrect evolutionary relationship.
From Flora Novae Angliae dichotomous key
8. Elymus trachycaulus (Link) Gould ex Shinners N
slender wild-rye. 1a. Agropyron caninum (L.) Beauv. var. pubescens Scribn. & J.G. Sm.; A. trachycaulum (Link) Malte var. glaucum (Pease & Moore) Malte; 1b. Agropyron trachycaulum (Link) Malte ex H.F. Lewis; A. trachycaulum (Link) Malte ex H.F. Lewis var. majus (Vasey) Fern.; A. trachycaulum (Link) Malte ex H.F. Lewis var. novae-angliae (Scribn.) Fern.; Triticum trachycaulum L. • CT, MA, ME, NH, RI, VT. Gravelly and ledgy river shores, cliffs and talus fields, open areas near the coast, peatlands, pond shores, roadsides, fields, swamp edges.
1a. Lemma awns 5–17 (–24) mm long, straight or curving outward from the axis of the spike; glume awns 0–10 mm long … 8a. E. trachycaulus ssp. glaucus (Pease & Moore) Cody
1b. Lemma awns wanting or represented by a short awn-tip (rarely as long as 5 mm and straight); glume awns absent or represented by a short awn-tip … 8b. E. trachycaulus ssp. trachycaulus
Subspecies glaucus is known from CT, MA, ME, NH, VT. Subspecies trachycaulus is known from CT, MA, ME, NH, RI, VT. Elymus subsecundus (synonym: E. trachycaulus var. unilateralis (Cassidy) Beetle) was reported from New England based on specimens with evident lemmas awns. These plants are, in fact, intermediate between E. trachycaulus and E. subsecundus and have been referred to by the epithet “ glaucus” by Fernald (1950b). Jozwik (1966) suggested that such plants with intermediate awn length and sometimes divergent awns are often hybrids between E. trachycaulus and E. subsecundus. If this hypothesis is confirmed, ssp. glaucus should be recognized at the specific level to ensure its name does not imply an incorrect evolutionary relationship.
Native to North America?
Yes
Sometimes confused with
- Elymus repens:
- anthers 3-7 mm long and plants not cespitose, with rhizomes (vs. E. trachycaulus, with anthers 1-2 mm long and plants cespitose, without rhizomes).
- Thinopyrum pycnanthum:
- anthers 5-7 mm long, and glumes acute at the apex, unawned or with a tiny mucro to 0.5 mm long (vs. E. trachycaulus, with anthers 1-2 mm long, and glumes long-acute at the apex, usually with an awn mostly 0.5-4 mm long).