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Panicum verrucosum — warty panicgrass

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Facts

Warty panicgrass is a distinctive grass of sandy and peaty shores and wetland margins. It enters New England at the northern limit of its range, and is found only in the southern New England states.

Habitat

Bogs, shores of rivers or lakes, wetland margins (edges of wetlands)

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
wetlands
New England state
  • Connecticut
  • Massachusetts
  • Rhode Island
Leaf blade width
3–10 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
1.7–2.2 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
  • there is 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
0.2–0.5 mm
Show all characteristics
  • Flowers

    Anther number
    0–3
    Awn on glume
    the glume has no awn
    Bristles below spikelets
    no
    Floret lower bract texture
    the lemma is hard and firm
    Floret number
    1–2
    Floret types within spikelet
    • NA
    • there are at least two distinct forms of florets within one spikelet
    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 flat or curved in cross-section
    Glume veins
    • 1
    • 3
    • 5
    • 7 or more
    Inflorescence arrangement
    the spikelets are uniform
    Inflorescence axis orientation
    the inflorescence axis is straight
    Inflorescence branches
    the flowers are attached to branches rather than to the main axis of the inflorescence
    Inflorescence length
    50–300 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
    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 flat or rounded if you cut across the midpoint
    Lemma surface
    the surface of the lemma is covered with small wart-like projections
    Lemma tip
    the lemma tip is a simple point, with or without an awn (long narrow extension ending in a point)
    Lemma vein number
    • 3
    • 5
    • 7 or more
    One or more florets
    • there is more than one floret per spikelet
    • there is one floret per spikelet
    Palea relative length
    palea is one half to fully as long as lemma
    Spikelet axis tip
    there is no extension of the spikelet axis beyond the tip of the spikelet
    Spikelet length
    1.7–2.2 mm
    Spikelets spiny
    the spikelets do not appear spiny
    Upper glume shape
    the upper glume is widest at or below the middle
  • Leaves

    Leaf auricles
    the leaves do not have auricles
    Leaf blade width
    3–10 mm
    Leaf ligule length
    0.2–0.5 mm
    Leaf ligule type
    the leaf ligule is in the form of a membrane with fine hairs
    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
    wetlands
    New England state
    • Connecticut
    • Massachusetts
    • Rhode Island
    Specific habitat
    • bogs
    • edges of wetlands
    • shores of rivers or lakes
  • Stem, shoot, branch

    Stem spacing
    the stems grow singly or a few together (they may form diffuse colonies)

Wetland status

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

In New England

Distribution

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

Conservation status

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

Connecticut
historical (S-rank: SH), special concern, extirpated (code: SC*)
Massachusetts
fairly widespread (S-rank: S4)

From Flora Novae Angliae dichotomous key

8.  Panicum verrucosum Muhl. N

warty panicgrass. CT, MA, RI. Sandy and/or peaty pond shores, low areas, and wetland edges.

Native to North America?

Yes

Sometimes confused with

Panicum virgatum:
upper glumes and lower lemmas not verrucose, with distinct veins (vs. P. verrucosum, with the upper glumes and lower lemmas distinctly verrucose with hemispherical protruberences, faintly veined).

Synonyms

  • Kellochloa verrucosa (Muhl.) Lizarazu, Nicola &

Family

Poaceae

Genus

Panicum