Japanese Bird's-Nest Fern

Description

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. 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. A global phylogeny of Asplenium published in 2020 divided the genus into eleven clades, which were given informal names pending further taxonomic study. A. antiquum belongs to the "Neottopteris clade", members of which generally have somewhat leathery leaf tissue. While the subclades of this group are poorly resolved, several of them share a characteristic "bird's-nest fern" morphology with entire leaves and fused veins near the margin. A. antiquum belongs to one of these subclades, together with A. antrophyoides, A. cymbifolium, A. humbertii, and A. phyllitidis. Other bird's-nest ferns, such as A. nidus sensu lato and A. australasicum, form a separate subclade which is not particularly closely related. 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 regular watering and can do with minimal soil (similar to an orchid). The soil should always be humid but not soaking wet.