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Schoenoplectus americanus

Species category

Weed

Common name

chairmaker's bulrush, American bulrush, Olney bulrush, Schoenoplectus

Diagnostic characters

Planting unit

AcheneAchene:
A dry, hard, one-chambered, one-seeded indehiscent fruit, as in buckwheat (Fagopyrum) or sunflower (Helianthus). The fruit wall is not united with the seed coat.

Shape

Broadly obovateObovate:
Inverted egg shaped with apical end the broadest.

Size

  • Length 3 mm 
  • Width 2.5 mm 
  • Thickness 1 mm 

Color

Light brown 

Texture

Smooth

Other structures

Remnants of style and scar are present.

Identification notes

This species is the lightest brown and largest of the three species shown. Its shape approaches a rounded triangle.

Noxious weed seed categories

Not listed

AOSA examination list

Not included

Nomenclature

Family

Cyperaceae

Valid name

Schoenoplectus americanus (Pers.) Volkart ex Schinz & R. Keller

Synonyms

Scirpus americanus Pers.
Scirpus chilensis Nees & Meyen ex Kunth
Scirpus conglomeratus Kunth
Scirpus olneyi A. Gray
Scirpus pungens Vahl var. longisetus Benth. & F. Muell.

From Left to Right:  1. Bolboschencus robustus 2. Schoenoplectus americanus 3. Schoenoplectus tabernaemontani .   Schoenoplectus americanus is the lightest brown and largest of the three species shown in the photo. Its shape approaches a rounded triangle.
From Left to Right:  1. Bolboschencus robustus 2. Schoenoplectus americanus 3. Schoenoplectus tabernaemontani.  Schoenoplectus americanus is the lightest brown and largest of the three species shown in the photo. Its shape approaches a rounded triangle.