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• Poaceae
• Poaceae Group 9
• Tripsacum
• Tripsacum dactyloides

Tripsacum dactyloides — eastern gamagrass

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

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)

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae