Naturalized                 Japanese climbing fern

Japonicum, from Japan.

Plants vinelike, terrestrial. Fronds to sev-eral meters long. Blades to 6-pinnate. Pinnae alternate. Pinnules alternate, sharp-tipped hairs on costae and veins, white, short, sparse; sterile pinnules to 4-pinnate, 8-15 em long, lanceolate, lobed or deeply incised at base; fertile pinnules 2-to 3-pinnate, 10-25 em long, triangular to long-triangular, short, much narrower than sterile pinnules. Ultimate sterile segments triangular to ovate; fertile segment margins bearing fingerlike, linear, sporangia-bearing lobes 2-10 mm long.

This widely cultivated fern is native to Japan, the Ryukyus, Taiwan, Korea, and China and was first collected growing naturally in Hawai 'i in 1936. It is now found climbing along roadside banks on shrubs and grasses along the main highway from a few miles north of Hilo to the southern end of Pepe'ekeo Scenic Drive, and uphill from the astronomy facility at the University of Hawai 'i Hilo Campus. Its range apparently is expanding, but a thorough evaluation of its local distribution has not been made.

Lygodium japonicum may be recognized by its up to 6-pinnate, vinelike growth pattern and fingerlike, linear, sporangia-bearing lobes on the fertile ultimate segments.