Ferns
Ferns are an ancient and diverse group of plants that has inhabited Earth for more than 300 million years. Today, there are an estimated 10,000 to 15,000 known species of ferns that are classified into about 40 different families. The reason these numbers vary is because certain groups of ferns are poorly studied, and new species are still being found in unexplored areas.
In nature, ferns make up an important component of many habitats, from the tropics through temperate regions, from deserts to rainforests, and from fully aquatic to epiphytic habits. They range in size from the giant tree ferns of our Australasian Area to tiny floating plants that you would be hard-pressed even to identify as a fern, such as the Pacific mosquitofern (Azolla filiculoides) found on the surface of most of the Garden’s ponds.
We’ve woven ferns into the tapestry of our habitat-based planting scheme, and display as many different kinds as possible in our collection. In all, the Garden has more than 400 accessions of 310 taxa of ferns. About 65% grow in the outdoor collections, and about 84% are of known wild origin, making them particularly valuable research specimens.
Similar to flowering plants, ferns have roots, stems, and leaves. But unlike other plants, they don’t produce flowers or seeds. Instead, they reproduce through tiny spores—or sometimes they can reproduce vegetatively, as with Woodwardia unigemmata.
Regions and History
Several Garden areas host outstanding collections of ferns. Tropical ferns are displayed in the Orchid, Fern, and Carnivorous Plant House and the Virginia Haldan Tropical House, and aquatic ferns are presented in the Aquatic Plant Display.
The Garden has benefited greatly from the curatorial support of Dr. Alan Smith, retired curator of Pteridophytes at UC Berkeley and Jepson Herbaria and former member of the Garden’s Faculty Advisory Committee. Dr. Smith is the author of Tropical Ferns of Mexico and is an internationally recognized expert in fern systematics and taxonomy. More than twenty published research papers have been based in part on the Garden’s fern collection; twelve of these are authored or co-authored by Dr. Smith. (Read a complete listing of publications that acknowledge support of the collections or facilities)
In 2007, the Garden’s fern collection was recognized as a collection of national significance by the Plant Collections Network (PCN), a joint program of the American Public Gardens Association and the USDA’s Agricultural Research Service. The program recognizes excellence in plant germplasm preservation and plant collections management.
Ferns Woven into our Collections
Dry-growing or Xerophytic Ferns
Xerophytic species native to California demonstrate that ferns can also prosper in the state’s dry summer climate, and should be considered part of our native plantings. While not strictly considered xerophytes, the familiar polypody ferns of California cope with our summer dry climate by going fully dormant when the rain stops, then springing into growth with the first rains of autumn. Sue Olsen’s book, Encyclopedia of Garden Ferns (2007) features images of xerophytic and other ferns from the Garden collection. Learn more about our Xerophytic Fern Display.
Tree ferns (Cyathea, Sphaeropteris, Dicksonia), native to New Zealand and Australia, create a striking display at the approach to the Australasian Area just beyond the Japanese Pool. Their trunks play host to epiphytic staghorn ferns (Platycerium) and they’re under-planted with terrestrial ferns, including Sadleria cyatheoides from Maui, Hawaii.
Another rich group of ferns is found throughout the Mexican and Central American Area. Mexican tree ferns of the genus Cyathea are just hardy enough to live in our cloud forest planting, as well as the few members of the otherwise tropical genus Elaphoglossum that we grow outdoors. With undivided, blade-like fronds, the genus Elaphoglossum is one of several with the common name tongue fern—indeed, the generic name translates as “elephant tongue.”
Members of the family Polypodiaceae are particularly common in the Mexican and Central American Area. Allied with the familiar polypodys of California, most of the Mexican and Central American taxa are now classified in the genus Pleopeltis. These ferns can form dense but not invasive stands in shaded areas with limited moisture. Two particularly interesting species from this area are the elegant Llavea cordifolia and the rare Mexican form of the Hart’s tongue fern, (Asplenium scolopendrium).
Learn more about how ferns reproduce on the Garden Blog:
Education
Fern Reproduction
Banner photo: Woodwardia unigemmata by Saxon Holt