Osmundas are not ferny in the traditional sense of lacy green, frothy lightness that the word fern implies to so many. Look instead for sturdy upright whorls of foliage that serve as backdrops in perennial beds and borders as well as in the difficult-to-manage poorly drained garden lowlands.
They are among the patriarchs of the fern world and can trace their origins back through geological time to at least the disappearing dinosaur days. Osmunda claytoniana is one seriously old species with fossil records, found in the Antarctic, dating back 200 million years to the Triassic era, the longest continuous life span of any living fern.
Unlike more highly evolved ferns that bear their spores on the frond's undersides, Osmunda spores are borne on primitive, specialized, modified fertile stalks that extend the full length of the frond as in O. cinnamomea and O. japonica or are restricted to the frond's tips as in O. regalis, or midsections of the vegetative fronds as in O. claytoniana. The sporangia have no indusia. Spores mature in a matter of days, are green,
and have a very short shelf life of about three weeks. Refrigeration extends their viability somewhat, and freezing (by simply wrapping the spores in a protective origami folded paper and stashing it atop the ice cream) improves their longevity significantly. While the spores germinate readily, the offspring are frustratingly slow to develop into mature plants.
There are approximately 10 to 16 species of these tall moisture-loving deciduous ferns. They are from acidic habitats and are extremely hardy and ornamental. Studies report that they, like so many ferns, are deer resistant. Winter-starved foraging slugs are attracted to the succulent, emerging stages of spring foliage on young plants, however, but comparable growth on mature plants is not particularly vulnerable. Osmunda cin-namomea and O. regalis have a strong preference for spongy soils where they can be admirably sun tolerant. All do well in traditional woodland mixes, although without acid soil and flooded feet, they will not reach the outstanding proportions for which they are widely admired.
Osmunda roots are black, fibrous, and wiry and are popularly shredded for use in specialized potting mixes designed for orchids and assorted epiphytes. They thread through the trunklike rhizomes that support the stubble of persistent old stipe bases. The stipe is frequently winged. The new growth is fleetingly downy, a down that is welcomed by hummingbirds for lining their nests. Fall color is yellow.
The name Osmunda is credited to Carl Linnaeus who reportedly named the genus after the Nordic god Thor, who was in turn the Saxon god Osmund. A more romantic interpretation credits the name to Osmund, a Saxon waterman on Loch Tyne, who upon hearing of an impending invasion from the Danes hid his wife and daughter in great stands of Osmunda (apparently successfully).
Osmunda regalis is referenced as far back as the late 1500s in British herbals as a treatment for a plethora of ailments. (Osmunda cinnamomea and O. claytoniana did not arrive in England until 1772.) Among other cures a poultice from the roots was popularly recommended for soothing burns and bruises and prescribed as a preventative for rickets. The Celts combined heather honey with the readily available, abundant supply of O. regalis spores to produce their mead. In North America various parts of the trio of native osmundas have been used by the Native Americans to cure an assortment of maladies. And today the young crosiers of O. japónica are offered in Japanese markets where they are considered a gourmet treat (although recent studies implicate the crosiers as potentially carcinogenic).
Osmunda cinnamomea Cinnamon fern
Epithet means "cinnamon brown."
Deciduous, 3 to 5 ft. (90 to 150 cm).Zones 2 to 10. Dimorphic.
description: The rhizome is upright, trunklike, and occasionally branching. The common name aptly describes the highly ornamental plumes of erect fertile fronds that are covered with cinnamon-colored shaggy sporangial cases following the shedding of their green spores in late spring. The light green lanceolate vegetative fronds, which encircle the fertile
Green spores fall from a freshly harvested small fertile pinna of Osmunda cinnamomea.
Unfurling Osmunda crosiers with their temporary coating of silvery down.
fronds, have tall tan stipes and tufts of whitish to rusty hairs at the base of the pinnate-pinnatifid pinnae.
range and habitat: This fern is common and locally abundant in wet acidic soils in northeastern Canada and the United States down to the Gulf states as well as the West Indies, Mexico, and South America.
culture and comments: The cinnamon fern is a very tolerant and willing garden subject that is especially handsome when combined with fellow color coordinates. The fertile fronds wither early in the summer and the sterile ones fade to a warm yellow-brown in autumn. The vegetative foliage can be confused with that of Osmunda claytoniana, however the cinnamon's pinnae hairs at the pinnae-stipe connection provide the distinction between the two. Spores should be harvested and sown as soon as ripe in early spring.
Var. fokiensis is the Asian counterpart of the cinnamon fern, differing in having black hairs as well as russet at the base of the sterile pinnae. It is native to Japan, Korea, and China and often botanically designated simply as Osmunda cinnamomea. Unfortunately the variety is rarely available in the trade.
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