Wolffia brasiliensis Weddell

Photo: Wolffia columbiana on left, Wolffia brasiliensis on right (W. columbinana left, W. brasiliensis right)

Pointed Water-meal

Habitat: Mesotrophic to eutrophic waters of lakes, rivers, and backwaters. [Open water (non-forested, wetland)]

Range: Maine, Connecticut and Massachusetts south to Virginia, west to Kansas.

Aids to Identification: This tiny aquatic plant is one of the smallest flowering plants. It is found floating low in the water with a small portion in contact with the air. The thalli (undifferentiated plant tissues) are ovoid and slightly asymmetrical (mostly 0.5-1.5 mm x 0.3-1.0 mm) with no veins or roots. Wolffia brasiliensis is similar in appearance to W. columbiana. Post-mortem, W. brasiliensis is punctate (dotted) with brown pigment-cells.

Photo: Wolffia columbiana on left, Wolffia brasiliensis on right (W. columbinana left, W. brasiliensis right)

Ecological characteristics: Wolffia species often grow in association with Lemna species (duckweed).

Phenology: Reproduces by vegetative budding. Flowers are rarely produced.

Family: Araceae

Synonyms: Former names include Wolffia papulifera C. Thompson; Bruniera punctata (Griseb.) Nieuwl.

Reason(s) for rarity: At northern limit of range.

Conservation considerations: None noted.