Phragmites australis (Cav.) Trin. ex Steud.

common reed

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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

This species of grass is introduced to North America and extremely invasive, greatly expanding its range since the early 20th century. It is detrimental to native plants and wildlife, quite difficult to eradicate, and tends to emerge earlier and be less susceptible to insect herbivory than the native strains.

Habitat

Anthropogenic (man-made or disturbed habitats), brackish or salt marshes and flats, fens, fresh tidal marshes or flats, marshes, shores of rivers or lakes, wetland margins (edges of wetlands)

Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf blade width
20–40 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
12–15 mm
Glume relative length
  • both glumes are as long or longer than all of the florets
  • neither glume is quite as long as 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 mm
Leaf sheath hair type
there are no hairs on the surface of the leaf sheath
Leaf ligule length
0.4–1.7 mm
Anther length
1.5–2 mm
Show All Characteristics
  • Flowers
    Anther length
    1.5–2 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
    3–10
    Floret types within spikelet
    there are at least two distinct forms of florets within one spikelet
    Glume awn length
    0 mm
    Glume keel
    the glume keels are smooth and hairless
    Glume relative length
    • both glumes are as long or longer than all of the florets
    • neither glume is quite as long as all of the florets
    Glume veins
    • 1
    • 3
    Glumes per spikelet
    2
    Inflorescence arrangement
    the spikelets are uniform
    Inflorescence axis orientation
    • 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 crowding
    the panicle is somewhat to very spread out, with clearly-evident branches
    Inflorescence length
    150–350 mm
    Inflorescence length to width ratio
    1.8–1.9
    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
    Inflorescence width
    80–200 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 base hair length
    6–12 mm
    Lemma base hairs
    the lemma has hairs at the base
    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
    the keel of the lemma is hairless
    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
    3
    Lower glume length
    2.5–5 mm
    Lower glume relative length
    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 length
    3–4 mm
    Reproductive system
    some flowers on the plant have both carpels and stamens, while other flowers have only one type of reproductive organ (polygamous)
    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
    12–15 mm
    Spikelet number per node
    0
    Spikelet pedicel
    the spikelets have pedicels
    Spikelet position
    the spikelets emerge from both the upper and lower halves of the inflorescence branches
    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
    4.5–7.5 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
  • Fruits or seeds
    Seed length
    2–3 mm
  • Growth form
    Horizontal rooting stem
    • no
    • yes
    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 few or no leaves coming from the base of the flowering stem
    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 have tiny fine hairs on them
    Leaf blade cross-section
    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
    15–40 cm
    Leaf blade texture
    the leaf blade is rough and sandpapery
    Leaf blade width
    20–40 mm
    Leaf ligule length
    0.4–1.7 mm
    Leaf ligule type
    • the leaf ligule is in the form of a membrane with fine hairs
    • the leaf ligule is in the form of fine hairs
    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
    • the leaf sheathes are reddish-brown and disintegrate or become shredded 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
  • Place
    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • brackish or salt marshes and flats
    • edges of wetlands
    • fens
    • fresh tidal marshes or flats
    • man-made or disturbed habitats
    • marshes
    • shores of rivers or lakes
  • Stem, shoot, branch
    Hairs at nodes
    the stem nodes are hairless or they have very sparse hairs
    Plant height
    150–400 cm
    Roots at lower stem nodes
    • no
    • yes
    Stem hairs
    • the stem has hairs on it
    • the stem is nearly to completely hairless
    Stem orientation
    • the stems are upright
    • the stems trail along the ground or on other plants through most or all of their length
    Stem spacing
    the stems grow singly or a few together (they may form diffuse colonies)
    Stem thickness at base
    5–15 mm

Wetland Status

Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

New England Distribution and Conservation Status

Distribution

Connecticut
present, invasive, prohibited
Maine
present
Massachusetts
present, invasive, prohibited
New Hampshire
present, invasive, prohibited
Rhode Island
present
Vermont
present, invasive, prohibited

Conservation Status

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

Connecticut
unrankable (S-rank: SU)
Massachusetts
unranked (S-rank: SNR)

ssp. americana

Vermont
extremely rare to rare (S-rank: S1S2)

ssp. americanus

Connecticut
unrankable (S-rank: SU)
Massachusetts
uncommon (S-rank: S3), #NAME? (code: #NAME?)

Native to North America?

No

Sometimes Confused With

Phragmites americanus:
middle and upper internodes of stem shiny and red-brown to dark red-brown during the growing season and ligules 1-1.7 mm long (vs. P. australis, with the middle and upper internodes of stem dull and tan during the growing season and ligules mostly 0.4-0.9 mm long).

Synonyms

  • Phragmites communis Trin.

Family

Poaceae

Genus

Phragmites

Notes on Subspecies and Varieties in New England

Our variety is Phragmites australis (Cav.) Trin. ex Steud. var. australis.

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Information from Dichotomous Key of Flora Novae Angliae

2.  Phragmites australis (Cav.) Trin. ex Steud. var. australis n

common reed. Phragmites communis Trin. • CT, MA, ME, NH, RI, VT. Fresh to brackish marshes, shores, ditches, fens.