Climbing fern

• Lygodium palmatum - American climbing fern
• Lygodium japonicum - Japanese climbing fern
• Lygodium microphyllum

The Climbing Ferns are an unusual group of plants (genus Lygodium) of tropical zones, with one temperate and one subtropical species. They are unique among plants in that the rachis, or midrib, of the frond is thin, flexible, and long - the frond unrolling with indeterminate growth and the rachis twining around supports, so that each frond forms a distinct vine. The fronds may be from three to ten meters long, depending on the species.

The one temperate species, the American Climbing Fern , (Lygodium palmatum, shown in photograph below) is rare throughout its range in the United States and requires intensely acid soil. On the other hand, two other species - Lygodium japonicum and Lygodium microphyllum - are exotic weeds throughout the deep south of the U. S., growing in a variety of soils. Lygodium japonicum is sparsely naturalized in Hawai'i.