Taeniatherum caput-medusae (L.) Nevski

Medusa-head

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

Medusa-head is a non-native grass that is considered a noxious weed in several western states, where it has invaded vast areas formerly dominated by native perennial grasses. In New England it is a rare visitor, having been collected only in Connecticut.

Habitat

Anthropogenic (man-made or disturbed habitats)

Characteristics

Habitat
terrestrial
New England state
Connecticut
Leaf blade width
0.2–2.5 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
6–12 mm
Glume relative length
neither glume is quite as long as all of the florets
Awn on glume
the glume has an awn
One or more florets
there is more than one floret per spikelet
Lemma awn length
20–110 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
0.2–0.6 mm
Anther length
0–1 mm
Show All Characteristics
  • Flowers
    Anther length
    0–1 mm
    Anther number
    0–3
    Awn on glume
    the glume has an awn
    Bristles below spikelets
    no
    Floret lower bract texture
    the lemma is thin and flexible
    Floret number
    2–3
    Floret types within spikelet
    there are at least two distinct forms of florets within one spikelet
    Glume awn length
    5–80 mm
    Glume relative length
    neither glume is quite as long as all of the florets
    Glume veins
    • 1
    • 3
    Glumes per spikelet
    2
    Inflorescence axis hairs
    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
    12–60 mm
    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)
    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
    20–110 mm
    Lemma awn number
    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 cross-section
    the lemma is flat or rounded if you cut across the midpoint
    Lemma hairs
    the lemma is hairless between the veins
    Lemma keel hairs
    NA
    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 long 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 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
    At least 0 mm
    Palea relative length
    palea is less than one half as long as lemma or absent
    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
    6–12 mm
    Spikelet number per node
    Up to 4
    Spikelet pedicel
    the spikelets do not have pedicels
    Spikelet pedicel length
    0 mm
    Spikelet position
    NA
    Spikelet shape
    the spikelets are another shape in profile
    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 relative length
    the upper glume is up to one half as long as the lowest lemma
    Upper glume shape
    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
    Seed length
    4–5.2 mm
  • 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
    Leaf auricles
    • the leaves do not have auricles
    • the leaves have auricles
    Leaf basal lobe hairy
    the lobes at the base of the leaf blades are hairless
    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 hairy
    Leaf blade length
    3–12 cm
    Leaf blade texture
    • the leaf blade is rough and sandpapery
    • the leaf blade is smooth, or it may have soft hairs
    Leaf blade width
    0.2–2.5 mm
    Leaf ligule length
    0.2–0.6 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
    New England state
    Connecticut
    Specific habitat
    man-made or disturbed habitats
  • Stem, shoot, branch
    Plant height
    5–70 cm
    Stem hairs
    the stem is nearly to completely hairless
    Stem node number
    3–6
    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
    • the stems grow singly or a few together (they may form diffuse colonies)

Wetland Status

Not classified

New England Distribution and Conservation Status

Distribution

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

Conservation Status

None

Native to North America?

No

Sometimes Confused With

Secale cereale

Synonyms

  • Elymus caput-medusae L.

Family

Poaceae

Genus

Taeniatherum

Notes on Subspecies and Varieties in New England

Our subspecies is Taeniatherum caput-medusae (L.) Nevski ssp. caput-medusae.

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Information from Dichotomous Key of Flora Novae Angliae

1.  Taeniatherum caput-medusae (L.) Nevski ssp. caput-medusae E

Medusa-head. Elymus caput-medusae L. • CT. Disturbed soil, waste places.