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Ottelia alismoides

Species category

Weed

Common name

ducklettuce

Diagnostic characters

Planting unit

True seedTrue seed:
A mature fertilized ovule consisting of an embryo, with or without and external food reserve (e.g., endosperm) enclosed by the testa.

Shape

EllipticElliptic:
Outline of an ellipse; greatest width midway sloping to an equally pointed apex and base.

Size

  • Length 1.5–1.7 mm 
  • Width 0.5–0.7 mm 
  • Thickness 0.5–0.7 mm 

Color

Brown

Texture

Covered with woolly hair

Other structures

HilumHilum:
The scar on the seed coat at the place of its detachment from the seed stalk (funiculus).
 is at the pointed, basalBasal:
The base of the fruit or seed opposite the apical end.
 end.

Identification notes

Woolly hair most dense at apexApical:
The distal end of the fruit or seed away from the point of attachment or attachment scar.
.

Noxious weed seed categories

Federal

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

AOSA examination list

Not included

Nomenclature

Family

Hydrocharitaceae

Valid name

Ottelia alismoides (L.) Pers.

Synonyms

Stratiotes alismoides L.

Ottelia alismoides. Dense woolly hair mostly at the apex. Photo by Julia Scher, USDA-APHIS-PPQ.
Ottelia alismoides. Dense woolly hair mostly at the apex. Photo by Julia Scher, USDA-APHIS-PPQ.
Ottelia alismoides. True seeds with a pointed hilum at the basal end. Photo by Julia Scher, USDA-APHIS-PPQ.
Ottelia alismoides. True seeds with a pointed hilum at the basal end. Photo by Julia Scher, USDA-APHIS-PPQ.
Ottelia alismoides. True seeds covered with woolly hair. Photo by Julia Scher, USDA-APHIS-PPQ.
Ottelia alismoides. True seeds covered with woolly hair. Photo by Julia Scher, USDA-APHIS-PPQ.