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Schedonorus giganteus — giant rye grass

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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

N/A

Habitat

Anthropogenic (man-made or disturbed habitats)

Characteristics

Habitat
terrestrial
New England state
Connecticut
Leaf blade width
4–18 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
8–20 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
10–18 mm
Leaf sheath hair type
there are no hairs on the surface of the leaf sheath
Leaf ligule length
0.5–2.5 mm
Anther length
2.5–3 mm
Show all characteristics
  • Flowers

    Anther length
    2.5–3 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
    3–10
    Floret types within spikelet
    all the florets within a spikelet are similar
    Glume awn length
    0 mm
    Glume keel
    NA
    Glume relative length
    neither glume is quite as long as all of the florets
    Glume shape
    the glume is flat or curved in cross-section
    Glume veins
    • 1
    • 3
    • 5
    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 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
    Inflorescence crowding
    the panicle is somewhat to very spread out, with clearly-evident branches
    Inflorescence length
    80–500 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
    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
    10–18 mm
    Lemma awn number
    the lemma has one awn on it
    Lemma awn orientation
    the awn of the lemma is straight
    Lemma base hair length
    0 mm
    Lemma base hairs
    the lemma is hairless or feels just a tiny bit rough at the base
    Lemma cross-section
    the lemma is flat or rounded if you cut across the midpoint
    Lemma keel hairs
    NA
    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 vein number
    5
    Lemma vein orientation
    the veins on the lemma come together near the tip
    Lower glume length
    4–7 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 longer than lemma
    • 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
    8–20 mm
    Spikelet number per node
    Up to 0
    Spikelet pedicel
    the spikelets have pedicels
    Spikelet shape
    the spikelets are lanceolate (lance-shaped, widest below the middle and tapering narrowly to the ends) in profile
    Spikelet width
    1.5–2.5 mm
    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
    5–8 mm
    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
    3–4.6 mm
  • Growth form

    Horizontal rooting stem
    no
    Lifespan
    the plant lives more than two years
  • Leaves

    Leaf 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 more or less flat in cross-section, or slightly folded or rolled inwards
    Leaf blade length
    10–40 cm
    Leaf blade width
    4–18 mm
    Leaf ligule length
    0.5–2.5 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
  • Place

    Habitat
    terrestrial
    New England state
    Connecticut
    Specific habitat
    man-made or disturbed habitats
  • Stem, shoot, branch

    Plant height
    Up to 150 cm
    Stem node number
    2–5
    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)

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

Schedonorus pratensis:
lemma awns absent or up to 4 mm long and leaf blades mostly 2–7 mm wide (vs. S. giganteus, with lemma awns 10–18 mm long and leaf blades mostly 6–18 mm wide).
Schedonorus arundinaceus:
lemma awns absent or up to 4 mm long and leaf blades mostly 4–12 mm wide (vs. S. giganteus, with lemma awns 10–18 mm long and leaf blades mostly 6–18 mm wide).

Synonyms

  • Bromus giganteus L.
  • Festuca gigantea (L.) Vill.
  • Lolium giganteum (L.) Darbyshire

Family

Poaceae

Genus

Schedonorus

From the dichotomous key of Flora Novae Angliae

2.  Schedonorus giganteus (L.) Holub E

giant rye grass. Bromus giganteus L.; Festuca gigantea (L.) Vill.; Lolium giganteum (L.) Darbyshire • CT. Waste areas, disturbed soil.