Nassella trichotoma

Species category

Weed

Common name

serrated tussock grass, serrated tussock

Diagnostic characters

Planting unit

FloretFloret:
A small flower in a clustered inflorescence (e.g., sunflower, grasses). In grasses, a floret consists of the lemma, palea, stamens, and pistil.

Shape

ObovateObovate:
Inverted egg shaped with apical end the broadest.

Size

  • Length 1.7–2.2 mm 
  • Width 0.8–1 mm 
  • Thickness 0.8–1 mm 

Color

Brown

Texture

CallusCallus:
The hard base of grass florets or spikelets, just above the point of disarticulation.
is copiously pubescentPubescent:
Having hairs.
. LemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.
is covered with transverseTransverse:
Set crosswise, crossing or at right angles.
row of tubercles.

Lemma

LemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.
encloses most of floretFloret:
A small flower in a clustered inflorescence (e.g., sunflower, grasses). In grasses, a floret consists of the lemma, palea, stamens, and pistil.
and has long geniculateGeniculate:
Bent at a sharp angle.
awn.

Palea

Covered by lemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.

Other structures

Short pointed callusCallus:
The hard base of grass florets or spikelets, just above the point of disarticulation.
present.

Identification notes

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 laterally compressed with the lemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.
enclosing most of 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.
. Lemma wider on one side than the other. Surface is rough with transverseTransverse:
Set crosswise, crossing or at right angles.
rows of tubercles. Long papery glumesGlume:
The pair of chaffy bracts that occur at the base of a grass spikelet, often completely enclosing it.
enclose a single 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

State Noxious Weed: Alabama, Arkansas, Delaware, Florida, Georgia, Hawaii, Illinois, Maryland, Michigan, Missouri, Mississippi, Nebraska, North Carolina, New Hampshire, Ohio, Oklahoma, Oregon, South Carolina, Texas, Vermont, Virginia, Washington, West Virginia, Wyoming
Federal

Learn more on ITP's Federal Noxious Weed Disseminules tool.

AOSA examination list

Included

More information

For more information, see ISMA fact sheet.

Nomenclature

Family

Poaceae

Valid name

Nassella trichotoma (Nees) Hack.

Synonyms

Stipa trichotoma Nees

 Nassella trichotoma.  The lemma encloses most of the floret and has a long geniculate awn. Photo by Julia Scher, USDA-APHIS-PPQ.
Nassella trichotoma. The lemma encloses most of the floret and has a long geniculate awn. Photo by Julia Scher, USDA-APHIS-PPQ.
 Nassella trichotoma.   Long papery glumes enclose a single floret where the lemma has a rough surface. Photo by Julia Scher, USDA-APHIS-PPQ.
Nassella trichotoma. Long papery glumes enclose a single floret where the lemma has a rough surface. Photo by Julia Scher, USDA-APHIS-PPQ.
 Nassella trichotoma.   Long papery glumes enclose a single floret. Photo by Julia Scher, USDA-APHIS-PPQ.
Nassella trichotoma. Long papery glumes enclose a single floret. Photo by Julia Scher, USDA-APHIS-PPQ.
 Nassella trichotoma.  Brown floret. Photo by Julia Scher, USDA-APHIS-PPQ.
Nassella trichotoma. Brown floret. Photo by Julia Scher, USDA-APHIS-PPQ.
 Nassella trichotoma.   Long papery glumes enclose a single floret. Photo by Julia Scher, USDA-APHIS-PPQ.
Nassella trichotoma. Long papery glumes enclose a single floret. Photo by Julia Scher, USDA-APHIS-PPQ.
 Nassella trichotoma.  Brown floret. Photo by Julia Scher, USDA-APHIS-PPQ.
Nassella trichotoma. Brown floret. Photo by Julia Scher, USDA-APHIS-PPQ.
 Nassella trichotoma.  Brown florets enclosed by papery glumes.
Nassella trichotoma. Brown florets enclosed by papery glumes.
 Nassella trichotoma.  Floret with a pubescent callus.
Nassella trichotoma. Floret with a pubescent callus.