Onychium japonicum, commonly known as carrot fern, is a perennial. The carrot fern is a species in the genus Onychium (claw fern) which contains 10 species and belongs to the family of the Adiantaceae (Maidenhair-fern Family). Onychium japonicum is a decidious plant with tripinnate leaves. The leaves are arranged opposite one another. They are linear with scalloped margins. It is native to India, China, Taiwan, south Korea, Japan, the Malay Peninsula and is naturalized in the Azores.

The Japanese carrot fern(Onychium japonicum) with very finely cut fronds to 60cm long, emerging from below ground. Slowly clump forming, a very graceful fern worthy of a place in any collection.
A novel chalcone derivative was isolated from Onychiumjaponicum and its structure was elucidated by spectroscopic methods. The isolated compound showed cytotoxic activity against the human carcinoma cell lines Hela and BEL-7402 in vitro.