Macarenia clavigera is a species of freshwater plant found primarily in the Amazon River basin. It belongs to the family Podostemaceae and is known for its unique adaptations to fast-flowing waters. This plant typically grows attached to rocks and other substrates, thriving in shallow, clear streams. The leaves of Macarenia clavigera are often small and ribbon-like, allowing them to withstand strong currents. This species plays a crucial role in its ecosystem by providing habitat and food for various aquatic organisms, contributing to the overall biodiversity of the Amazonian waterways.