Tripsacum dactyloides

Species category

Agricultural, Revegetation or Rangeland, Weed

Common name

eastern gamagrass

Diagnostic characters

Planting unit

Rachis segmentRachis segment:
A segment of the central axis of the inflorescence (rachis). In some species (e.g. Andropogon) separation of the sessile spikelets occurs when the rachis disarticulates at the spikelet bases leaving the segment of the rachis between spikelets attached to the lower spikelet.

Shape

Blocky 

Size

  • Length 8–10 mm 
  • Width 4–4.5 mm 
  • Thickness 4–4.5 mm 

Color

Brown

Texture

Rough 

Lemma

The lemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.
is enclosed in the rachis segmentRachis segment:
A segment of the central axis of the inflorescence (rachis). In some species (e.g. Andropogon) separation of the sessile spikelets occurs when the rachis disarticulates at the spikelet bases leaving the segment of the rachis between spikelets attached to the lower spikelet.
and hard glumesGlume:
The pair of chaffy bracts that occur at the base of a grass spikelet, often completely enclosing it.
.

Palea

The paleaPalea:
One of the thin bracts of grass floret enclosing the fruit (caryopsis) that is located on the side opposite the embryo.
is enclosed in the rachis segmentRachis segment:
A segment of the central axis of the inflorescence (rachis). In some species (e.g. Andropogon) separation of the sessile spikelets occurs when the rachis disarticulates at the spikelet bases leaving the segment of the rachis between spikelets attached to the lower spikelet.
and hard glumesGlume:
The pair of chaffy bracts that occur at the base of a grass spikelet, often completely enclosing it.
.

Other structures

The floretFloret:
A small flower in a clustered inflorescence (e.g., sunflower, grasses). In grasses, a floret consists of the lemma, palea, stamens, and pistil.
is not visible.

Identification notes

Seed unitSeed unit:
The structure usually regarded as a seed in planting practices and in commercial channels, consisting of a true seed with or without accessory structures, as defined in Section 2.6 of the AOSA Rules. See also true seed.
is a section of the rachisRachis:
The central axis of an inflorescence.
which contains one floretFloret:
A small flower in a clustered inflorescence (e.g., sunflower, grasses). In grasses, a floret consists of the lemma, palea, stamens, and pistil.
.

Noxious weed seed categories

Not listed

AOSA examination list

Not included

Nomenclature

Family

Poaceae

Valid name

Tripsacum dactyloides (L.) L.

Synonyms

Coix dactyloides L.
Tripsacum dactyloides (L.) L. var. occidentale Cutler & Anders.

 Tripsacum dactyloides.  Rachis segment that contains one floret that is not visible.
Tripsacum dactyloides. Rachis segment that contains one floret that is not visible.
 Tripsacum dactyloides.  Lateral view of spikelet. Photo by Steve Hurst, USDA-NRCS
Tripsacum dactyloides. Lateral view of spikelet. Photo by Steve Hurst, USDA-NRCS