Rotala rotundifolia

Rotala rotundifolia is a perennial wetland herb native to Asia and widely cultivated as an aquarium plant. Creeping stems root in saturated soil, while upright shoots carry opposite leaves that change from rounded forms above water to narrower forms when submerged. Slender spikes of small pink flowers develop on emersed growth. The species favors strong light, constant moisture, and nutrient-rich wet ground. Photographed in Florida.