Megathyrsus maximus

Species category

Agricultural

Common name

guineagrass

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

Elliptic 

Size

  • Length 3.5–3.8 mm 
  • Width 1.2–1.6 mm 
  • Thickness 1–1.2 mm 

Color

Yellow with tip 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.
dark brown

Texture

Tubercles on lemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.
form faint transverseTransverse:
Set crosswise, crossing or at right angles.
ridges

Lemma

Hard; basalBasal:
The base of the fruit or seed opposite the apical end.
half broadest; no awnAwn:
A narrow, bristle-like organ, as on the glumes or lemmas of grasses (Poaceae).
; slightly arched; nerves obscure.

Palea

Hard and slightly arched

Other structures

Small scar

Identification notes

Unit is mostly found as a floretFloret:
A small flower in a clustered inflorescence (e.g., sunflower, grasses). In grasses, a floret consists of the lemma, palea, stamens, and pistil.
; however, spikeletsSpikelet:
One or more florets that are subtended by a pair of bracts called glumes. Spikelets are pedicellate if located on a pedicle and sessile if attached directly to the rachis. Often spikelets with single florets have remnants of a second floret, usually a lemma.
are found. SpikeletsSpikelet:
One or more florets that are subtended by a pair of bracts called glumes. Spikelets are pedicellate if located on a pedicle and sessile if attached directly to the rachis. Often spikelets with single florets have remnants of a second floret, usually a lemma.
consist of a basalBasal:
The base of the fruit or seed opposite the apical end.
first glumeGlume:
The pair of chaffy bracts that occur at the base of a grass spikelet, often completely enclosing it.
, then equal second glumeGlume:
The pair of chaffy bracts that occur at the base of a grass spikelet, often completely enclosing it.
and sterile lemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.
, and finally 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.
.

Noxious weed seed categories

Not listed

AOSA examination list

Not included

More information

For more information, see ISMA fact sheet.

Nomenclature

Family

Poaceae

Valid name

Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs

Synonyms


Panicum gongylodes Jacq.
Panicum hirsutissimum Steud.
Panicum jumentorum Pers.
Panicum laeve Lam.
Panicum maximum Jacq.
Panicum maximum var. gongylodes (Jacq.) Döll
Panicum maximum var. maximum Jacq.
Panicum maximum var. pubiglume K. Schum.
Panicum maximum var. trichoglume Robyns
Panicum maximum f. pubiglume (K. Schum.) K. Schum. ex Peter
Panicum polygamum Sw.
Panicum polygamum var. gongylodes (Jacq.) E. Fourn.
Panicum praticola Salzm. ex Döll
Panicum scaberrimum Lag.
Panicum trichocondylum Steud.
Urochloa maxima (Jacq.) R.D. Webster
Urochloa maxima var. trichoglumis (Robyns) R.D. Webster

 Megathyrsus maximus.  Yellow florets with dark brown tips.
Megathyrsus maximus. Yellow florets with dark brown tips.