Lygodium microphyllum (commonly known as, variously, climbing maidenhair fern, Old World climbing fern, small-leaf climbing fern, or snake fern) is a climbing fern originating in tropical Africa, South East Asia, Melanesia and Australia. It is an invasive weed in the US States of Florida and Alabama where it invades open forest and wetland areas. The type specimen was collected in the vicinity of Nabúa, on the Island of Luzon in the Philippines by Luis Née.