Sporobolus compositus

Species category

Revegetation or Rangeland

Common name

composite dropseed, dropseed

Diagnostic characters

Planting unit

CaryopsisCaryopsis:
The single-seeded fruit or grain of the grass family (Poaceae); the fruit wall (pericarp) is united with the seed coat (testa).

Shape

OvalOval:
Broadly elliptic.

Size

  • Length 4.5–6 mm 
  • Width 0.5–1 mm 
  • Thickness 0.5–1 mm 

Color

Yellow lemmaLemma:
One of two bracts of the grass floret; it is located on the side nearest the embryo and opposite the rachilla.
and paleaPalea:
One of the thin bracts of grass floret enclosing the fruit (caryopsis) that is located on the side opposite the embryo.
, red-brown caryopsisCaryopsis:
The single-seeded fruit or grain of the grass family (Poaceae); the fruit wall (pericarp) is united with the seed coat (testa).

Texture

Longitudinal rows of minute tubercles

Lemma

Thin and papery

Palea

Thin and papery

Other structures

EmbryoEmbryo:
A rudimentary plant contained in a seed, usually consisting of a more or less differentiated axis and attached cotyledon(s).
is half the length of the caryopsisCaryopsis:
The single-seeded fruit or grain of the grass family (Poaceae); the fruit wall (pericarp) is united with the seed coat (testa).
.

Identification notes

Most units are caryopsesCaryopsis:
The single-seeded fruit or grain of the grass family (Poaceae); the fruit wall (pericarp) is united with the seed coat (testa).
, but some are floretsFloret:
A small flower in a clustered inflorescence (e.g., sunflower, grasses). In grasses, a floret consists of the lemma, palea, stamens, and pistil.
and even 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.
. CaryopsisCaryopsis:
The single-seeded fruit or grain of the grass family (Poaceae); the fruit wall (pericarp) is united with the seed coat (testa).
is laterally compressed and closely covered with fine rows of minute tubercles.

Noxious weed seed categories

Not listed

AOSA examination list

Not included

More information

For more information, see ISMA fact sheet, Sporobolus spp.

Nomenclature

Family

Poaceae

Valid name

Sporobolus compositus (Poir.) Merr

Synonyms

Sporobolus asper (P. Beauv.) Kunth var. canovirens (Nash) Shinners
Sporobolus asper (P. Beauv.) Kunth var. clandestinus (Biehler) Shinners
Sporobolus canovirens Nash
Sporobolus clandestinus (Biehler) Hitchc. var. canovirens (Nash) Steyerm. & Kucera
Sporobolus compositus (Poir.) Merr. var. clandestinus (Biehler) Wipff & S.D. Jones
Sporobolus longifolius (Torr.) Alph. Wood

 Sporobolus compositus.  Caryopsis that is laterally compressed and closely covered with fine rows of minute tubercles. 
Sporobolus compositus. Caryopsis that is laterally compressed and closely covered with fine rows of minute tubercles. 
 Sporobolus compositus.  Caryopsis that is laterally compressed and closely covered with fine rows of minute tubercles. 
Sporobolus compositus. Caryopsis that is laterally compressed and closely covered with fine rows of minute tubercles. 
From Left to Right: 1. Bottom.  Sporobolus neglectus  2. Bottom.  Sporobolus airoides  3. Bottom.  Sporobolus clandestinus  4. Top.  Sporobolus compositus  5. Top.  Sporobolus giganteus  6. Top.  Sporobolus cryptandrus.
From Left to Right: 1. Bottom. Sporobolus neglectus 2. Bottom. Sporobolus airoides 3. Bottom. Sporobolus clandestinus 4. Top. Sporobolus compositus 5. Top. Sporobolus giganteus 6. Top. Sporobolus cryptandrus.
From Left to Right: 1.  Sporobolus compositus  2.  Sporobolus airoides  3.  Sporobolus cryptandrus . Caryopsis with an embryo that is half the length of the caryopsis.
From Left to Right: 1. Sporobolus compositus 2. Sporobolus airoides 3. Sporobolus cryptandrus. Caryopsis with an embryo that is half the length of the caryopsis.