Asplenium antiquum

Asplenium antiquum is a fern of the group known as bird's-nest ferns. In Japanese it is known by ō-tani-watari and tani-watari. The fern is native to temperate East Asia, in China, Japan, Korea, and Taiwan on cliffs, dark forests, and tree trunks. It is an IUCN endangered species in its native habitats. Asplenium antiquum is an evergreen fern, 2–3 ft. (60–90 cm). It has bright green, arching blades with a pointed end and a strong midrib. Asplenium antiquum can readily be distinguished from the closely related Asplenium nidus by its fronds of uniform width. The fern is commonly available in the plant nursery trade as an ornamental plant in subtropical climates, and a house plant in the United States and Europe in zones 9 and 10. It requires high humidity and bright indirect light, so does best in a greenhouse or terrarium if grown indoors. It needs minimal watering and minimal soil (similar to an orchid). Mearnsetin 3,7-dirhamnoside, a glycoside of the flavonol mearnsetin, can be found in A. antiquum.