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Panicum amarum — bitter panicgrass

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Facts

Bitter panicgrass inhabits beaches, dunes and sandy roadsides along the coast. There are two subspecies in New England. One (Panicum amarum ssp. amarum) is an endangered species from Connecticut and Rhode Island, while the other (P. amarum ssp. amarulum) is introduced, and found in Connecticut and Massachusetts.

Habitat

Anthropogenic (man-made or disturbed habitats), coastal beaches (sea beaches), dunes

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Massachusetts
Leaf blade width
2–13 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
4–7.7 mm
Glume relative length
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
  • 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
1–5 mm
Show all characteristics

  • Flowers

    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 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
    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
    • 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 branches coming off the lowest stem node
    At least 1
    Inflorescence crowding
    the panicle is somewhat to very congested (crowded), and the branches may not be clearly seen without close inspection
    Inflorescence length
    100–800 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 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
    • 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
    4–7.7 mm
    Spikelets spiny
    the spikelets do not appear spiny
    Upper glume shape
    the upper glume is widest at or below the middle

  • Growth form

    Lifespan
    the plant lives more than two years
    Rhizomes
    yes
    Roots
    the plant has rhizomes (horizontal underground stem with roots growing from it)

  • Leaves

    Leaf auricles
    the leaves do not have auricles
    Leaf blade hairs
    the leaf blade is hairless, but it may have tiny prickles that give it a sand-papery feel
    Leaf blade width
    2–13 mm
    Leaf ligule length
    1–5 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
    terrestrial
    New England state
    • Connecticut
    • Massachusetts
    Specific habitat
    • dunes
    • man-made or disturbed habitats
    • sea beaches

  • Stem, shoot, branch

    Hairs at nodes
    the stem nodes have hairs that stand out at a shallow angle, or they curve downwards
    Plant height
    20–250 cm
    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
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
rare (S-rank: S2), threatened (code: T)

ssp. amarulum

Massachusetts
not applicable (S-rank: SNA)

ssp. amarum

Rhode Island
extremely rare (S-rank: S1), concern (uncertain) (code: C*)

var. amarulum

Connecticut
unranked (S-rank: SNR)

var. amarum

Connecticut
rare (S-rank: S2), threatened (code: T)

Subspecies and varieties

Subspecies amarulum is known from CT, MA and is considered non-native (original populations are believed to have been intentionally introduced). Subspecies amarum is known from CT, RI. It is both native and of conservation concern.

From Flora Novae Angliae dichotomous key

1.  Panicum amarum Ell. nC

bitter panicgrass. 1a. Panicum amarulum A.S. Hitchc. & Chase; P. amarum Ell. var. amarulum (A.S. Hitchc. & Chase) P.G. Palmer • CT, MA, RI. Atlantic coast beaches, dunes, sandy roadsides.

1a.  Lower glume with 3–5 veins, the midvein smooth apically; spikelets 4–5.9 mm long; panicles with 2 or more primary branches per node; rhizomes short and/or ascending; reproductive stems often cespitose, mostly 100–250 cm tall

… 1a. P. amarum ssp. amarulum (A.S. Hitchc. & Chase) Freckmann & Lelong

1b.  Lower glume with 7–9 veins, the midvein minutely scabrous apically; spikelets 4.7–7.7 mm long; panicles with 1 or 2 primary branches per node; rhizomes horizontally elongate; reproductive stems usually solitary, mostly 20–150 cm tall … 1b. P. amarum ssp. amarum

Subspecies amarulum is known from CT, MA and is considered non-native (original populations are believed to have been intentionally introduced). Subspecies amarum is known from CT, RI. It is both native and of conservation concern.

Native to North America?

Yes and no (some introduced)

Sometimes confused with

Panicum miliaceum:
plants annual and stems and/or sheaths pubescent(vs. P. amarum, with plants perennial from short to long rhizomes and stems and sheaths glabrous).
Panicum virgatum:
panicle open, with ascending to spreading branches, plants sometimes pubescent on the leaf sheaths and/or blades (vs. P. amarum, with panicle contracted, with strictly ascending to appressed branches, and plants glabrous throughout).

Synonyms

  • Panicum amarulum A.S. Hitchc. & Chase
  • Panicum amarum Ell. var. amarulum (A.S. Hitchc. & Chase) P.G. Palmer

Family

Poaceae

Genus

Panicum