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Panicum philadelphicum — Philadelphia panicgrass

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Facts

Philadelphia panicgrass inhabits river shores, sandbars, fields, roadsides, ditches and open woodlands. There are two varieties in New England. One (Panicum philadelphicum var. campestre) is rare and found in Connecticut and Massachusetts, while the other (P. philadelphicum var. philadelphicum) is found throughout the region.

Habitat

Meadows and fields, shores of rivers or lakes, woodlands

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
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf blade width
2–12 mm
Inflorescence branches
the flowers are attached to branches rather than to the main axis of the inflorescence
Spikelet length
1.8–2.4 mm
Glume relative length
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 hairs on the surface of the leaf sheath, and some of the hairs have blisters at their bases
Leaf ligule length
0.5–1.5 mm
Anther length
0.9–1.2 mm
Show all characteristics

  • Flowers

    Anther length
    0.9–1.2 mm
    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
    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 crowding
    the panicle is somewhat to very spread out, with clearly-evident branches
    Inflorescence length
    40–240 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 disintegration
    the spikelet breaks off above the glumes, so that after the florets fall off, the glumes remain
    Spikelet length
    1.8–2.4 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 only a single year or less

  • Leaves

    Leaf auricles
    the leaves do not have auricles
    Leaf blade width
    2–12 mm
    Leaf ligule length
    0.5–1.5 mm
    Leaf ligule type
    the leaf ligule is in the form of 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 hairs on the surface of the leaf sheath, and some of the hairs have blisters at their bases
    Leaf sheath hairs
    there are 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
    • meadows or fields
    • shores of rivers or lakes
    • woodlands

  • Stem, shoot, branch

    Stem spacing
    the stems grow close together in compact clusters or tufts

Wetland status

Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)

In New England

Distribution

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

Conservation status

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

New Hampshire
historical (S-rank: SH), endangered (code: E)

ssp. gattingeri

Massachusetts
rare (S-rank: S2), special concern (code: SC)

ssp. philadelphicum

Massachusetts
uncommon (S-rank: S3), special concern (code: SC)

var. philadelphicum

Vermont
extremely rare (S-rank: S1)

Subspecies and varieties

Variety campestre is known from CT, MA and is of regional conservation concern. Variety philadelphicum is known from CT, MA, ME, NH, RI, VT.

From Flora Novae Angliae dichotomous key

6.  Panicum philadelphicum Bernh. ex Trin. NC

Philadelphia panicgrass.  6a. Panicum capillare L. var. campestre Gattinger; P. gattingeri Nash; P. philadelphicum Bernh. ex Trin. ssp. gattingeri (Nash) Freckmann & Lelong • CT, MA, ME, NH, RI, VT. River shores, sand/silt bars, low areas in fields, roadsides, ditches, open woodlands. Darbyshire and Cayouette (1995) showed that the two taxa treated below as varieties 
are morphologically similar and are closer to each other than any other members of the Panicum capillare complex.

1a.  Leaf blades usually 6–12 mm wide; uppermost leaf (i.e., the one immediately below the inflorescence) with a blade length to sheath length ratio of 1.4–2.6, the blade usually more than 50% as tall as the panicle; pedicels spreading, provided with scabrules that slightly, 
if at all, increase in length toward the apex of the pedicel; apex of the upper glume and 
lower lemma straight; spikelets usually disarticulating below the glumes, leaving behind an empty pedicel … 6a. P. philadelphicum var. campestre (Gatt.) A. Haines

1b.  Leaf blades usually 2–6 mm wide; uppermost leaf with a blade length to sheath length ratio of 0.8–1.6, the blade usually less than 50% as tall as the panicle; pedicels appressed, provided with scabrules that noticeably increase in length toward the apex of the pedicel; apex of the upper glume and lower lemma curving over the upper floret; spikelets usually disarticulating on the rachilla first, the upper floret dropping prior to the more tardily disarticulating glumes and sterile lemma … 6b. P. philadelphicum var. philadelphicum

Variety campestre is known from CT, MA and is of regional conservation concern. Variety philadelphicum is known from CT, MA, ME, NH, RI, VT.

Native to North America?

Yes

Sometimes confused with

Panicum tuckermanii:
anthers 0.5–0.75 mm long, uppermost leaf with a blade length to sheath length ratio of 2–3, usually enclosing the lower branches of the inflorescence in the sheath, and spikelets usually 1.4–1.8 mm long at maturity (vs. P. philadelphicum, with anthers mostly 0.8–1 mm long, uppermost leaf with a blade length to sheath length ratio of mostly 0.8–1.8, usually not enclosing the lower branches of the inflorescence in the sheath).
Panicum capillare:
panicle usually more than 50% of the total plant height, spikelets mostly 2.3– 4 mm long, and upper floret usually light brown-yellow to light brown (vs. P. philadelphicum, with the panicle usually less than 50% of the total plant height, spikelets 1.4–2.4 mm long, and upper floret usually dark brown at maturity).

Family

Poaceae

Genus

Panicum