San Francisco Botanical Garden - Gardens

In rocky crevices and open forests in New Zealand where there is plenty of shade, grows one of the most popular of house plants, the button fern. Its fronds (leaves) with its small, round forest-green pinnae (segments), occupy window sills and coffee tables in homes from Australia to Europe. Look under each pinna and see the sori, the clusters of spore cases that contain dusky, dust-like single-cell spores, running along its margins. Spores are the fern's means of reproduction, and every fern has its own distinctive pattern of sori on the underside of its pinnae.

Ferns are one of the earth's oldest inhabitants. Millions of years ago the “button fern” had ancestors covering the world before the age of dinosaurs. Eons of time passed and great oceans submerged the fern forests. Compression and volcanic activity on layers of sediment eventually created today's world-wide beds of fossil fuel. Ten thousand species of ferns exist in the world today.

From the Library Terrace, walk down the path through the East Asia Garden, toward the California Native Garden. On your right is a pond and nearby, under a large weeping cherry, is the button fern.