Common Duckweed
Lemna minor

Family: Duckweed (Lemnaceae)
AKA: Lesser Duckweed
Photo taken on: July 13, 2020
Location: Agua Caliente Spring, Abiquiu, NM
Life Zones: Plains to foothills
Habitat: Shallow, still or slow-moving water

Grows free-floating on water with small, oval fronds, less than 1/4" across, and a single root dangling to 6" long. Flowers are rarely produced, propagation is by the forming of new shoots from buds.

Seen growing here with Watercress.

Flora of North America reference.