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Tripsacum dactyloides — eastern gamagrass

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Facts

Eastern gamagrass inhabits Central and South America and the eastern, southern and central United States, reaching the northeastern limit of its range in New England. In our region it is a very rare grass of the upper edges of salt marshes, salt meadows, riversides and fields near the coast. It can reach heights near 3 m (10 feet), and is increasingly popular as a garden ornamental.

Habitat

Anthropogenic (man-made or disturbed habitats), marshes, meadows and fields, shores of rivers or lakes

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
  • Massachusetts
  • Rhode Island
Leaf blade width
9–45 mm
Inflorescence branches
  • the flowers are attached to branches rather than to the main axis of the inflorescence
  • there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious
Spikelet length
6–8 mm
Glume relative length
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 one floret per spikelet
Lemma awn length
0 mm
Leaf ligule length
1–3 mm
Show all characteristics
  • Flowers

    Anther number
    At least 0
    Awn on glume
    the glume has no awn
    Floret types within spikelet
    there are at least two distinct forms of florets within one spikelet
    Glume relative length
    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
    0
    Inflorescence arrangement
    the plant has two types of spikelets with different reproductive structures
    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
    • there are no branch points between the base of the inflorescence axis and the flowers, or they are not obvious
    Inflorescence type (general)
    • the inflorescence is a spike, or is spike-like, lacking obvious branches
    • the spikelets are borne on stalks or on branches
    Inflorescence type (specific)
    • the inflorescence has pairs (or trios) of spikelets that are similar to each other in structure and size, with at least one of the spikelets on a stalk
    • the inflorescence has pairs (or trios) of spikelets, but with one always either missing a stalk or on a shorter stalk than the other
    • the inflorescence is a spike (a long unbranched stem with flowers along it that lack stalks)
    Inforescence position
    the spikelets are mainly carried at the end of the stem
    Lemma awn base
    NA
    Lemma awn length
    0 mm
    Lemma awn number
    the lemma has no awn
    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
    0
    One or more florets
    there is one floret per spikelet
    Spikelet axis tip
    there is no extension of the spikelet axis beyond the tip of the spikelet
    Spikelet disintegration
    the spikelet breaks off below the glumes
    Spikelet length
    6–8 mm
    Spikelets spiny
    the spikelets do not appear spiny
  • Leaves

    Leaf auricles
    the leaves do not have auricles
    Leaf blade width
    9–45 mm
    Leaf ligule length
    1–3 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 hairs
    • there are hairs on the surface of the leaf sheath
    • there are no hairs on the surface of the leaf sheath
  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Massachusetts
    • Rhode Island
    Specific habitat
    • man-made or disturbed habitats
    • marshes
    • meadows or fields
    • shores of rivers or lakes
  • Stem, shoot, branch

    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

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

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
uncommon (S-rank: S3)
Massachusetts
extremely rare (S-rank: S1), endangered (code: E)
Rhode Island
rare (S-rank: S2), concern (code: C)

From Flora Novae Angliae dichotomous key

1.  Tripsacum dactyloides (L.) L. NC

eastern gamagrass. Coix dactyloides L. • CT, MA, RI. Upper border of saline marshes, salt meadows, river shores and banks, dry fields near the coast.

Native to North America?

Yes

Sometimes confused with

Aegilops cylindrica

Family

Poaceae

Genus

Tripsacum