old world climbing fern Lygodiummicrophyllum (Cav.) R. Br.
Appearance
Lygodium microphyllum is a perennial climbing fern that can reach lengths of more than 90 ft. (27.4 m).
Foliage
Vines are thin, wiry, and remain green throughout winter. The fronds (leaves of a fern) are opposite, singly compound, 2-5 in. (5-12.7 cm) long with thick, usually unlobed leaflets. Fertile fronds have lobes around the margin, where sporangia are covered with rolled leaf tissue. It has two types of leaflets on its climbing leaf. The leaflet with the simple (unlobed) outline is a normal vegetative leaflet. The more convoluted leaflet has sporangia along its margin.
Flowers
This plant does not produce flowers.
Fruit
The sporangia produces spores leading to the development of gametophytes. The gametophytes are usually small, and difficult to spot.
Ecological Threat
Lygodium microphyllum is a serious invader of swamps, glades, and hammocks. It can form dense mats that smother understory vegetation, shrubs and trees. This plant also increases fire risks. Thick mats of dead fronds that grow into trees act as fire ladders, bringing the fires into the tree canopies. It is native to Africa, Australia and Southeast Asia and was first found naturalized in the United States in 1965.