Duckweed

You may protest at first, but Lemna gibba or minor is floating on streamlet while the L. trisulca is submerged beneath it.

Someday I will remember to use a polarizing filter for aquatic images like this.

Plant collected 8/19/14, photographed later but not vouchered. Note dorsal row of papules along the midline. Associates: Wolffia columbiana and Wolffia brasiliensis. Identifications verified by Wayne Armstrong.

Plant collected 8/19/14, photographed later but not vouchered. Note reddish anthocyanin patches on ventral surface. Associates: Wolffia columbiana and Wolffia brasiliensis. Identifications verified by Wayne Armstrong.