MAIDENHAIR

maidenhair, in botany, the common name for a fern, _adiantum capillus-veneris_, characterized by the spreading hairlike branches of the frond, the ultimate pinnules of which are 1⁄2 to 1 in. long with a rounded crenate outer edge and repeatedly forked veins; the sori (or masses of spore-capsules) are in the crenatures of the pinnules, and are protected by a kidney-shaped involucre. the plant is widely distributed in temperate and tropical regions, and is occasionally found in the western counties of england, the isle of man, and west ireland, growing on damp rocks or walls especially near the sea. the genus _adiantum_ is a large one containing many handsome species both tropical and temperate, well known in greenhouse and hothouse cultivation. maidenhair-tree is a popular name for _ginkgo biloba_, a remarkable and handsome gymnospermous tree, the fan-shaped leaves of which with their forked veins recall those of the maidenhair (see gymnosperms).