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Aquatic and Wetland Vascular Plants of the Northern Great Plains

Wolffia Horkel -- Water-meal


Minute, thalloid, rootless plants floating at or just beneath the surface, often abundant and forming a granular scum on the water surface, usually mixed with other Lemnaceae; fronds flat on the upper surface (in those included here), solitary or often paired. Reproductive pouch 1, near the base of the frond. Flowers rare and very minute, consisting of 1 stamen (male flower) and 1 pistil (female flower) in the pouch. Fruit globose, 1-seeded. Reproduction mainly by budding.

These plants are the smallest of all flowering plants and are easily overlooked in mixed culture with larger duckweeds. The tiny thalli are fairly easily detected by their granular or mealy feel to the touch and their tendency to adhere to the skin as the hand is withdrawn from the water.

Lead Characteristic Go To
1 Fronds ellipsoid to oblong when viewed from above, 1 1/3 - 2X longer than wide, with a raised pointed apex, usually brown-punctate when dried. W. borealis
1 Fronds orbicular to broadly ovoid when viewed from above, 1-1 1/3X longer than wide, not raised and pointed at the apex, not brown-punctate. W. columbiana


60. Lemnaceae, the Duckweed Family
3. Wolffia Horkel -- Water-meal
1. Wolffia borealis (Engelm.) Landolt
2. Wolffia columbiana Karst.


Return to Family -- Lemnaceae - The Duckweed Family
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