Cinnamon Ferns

Cinnamon Ferns -- © Dave Spier

The Cinnamon Fern is a large, coarse and attractive plant usually found in shaded to partly-shaded bog edges, swampy areas, streambanks and similar moist woodlands often in association with sphagnum moss. The green, vegetative leaves (fronds) grow in circular, vase-like clusters reaching a height of three feet or more. Around the end of May or early June, the separate, fertile fronds rising in the center ripen into bright, rusty-red (cinnamon-colored) stalks in preparation for releasing their spores.

The generally accepted scientific name, Osmunda cinnamomea, refers to the Saxon god, Osmunder, who supposedly hid his family from danger in a large colony of these ferns. In addition to creating new plants from spores, Cinnamon Ferns can form these widespread, monotypical stands by extending the heavy, hairy rootstocks. New plants are added at the front while the oldest bases eventually wither and decay. Theoretically, a single plant can continue to grow "forever" in this fashion.

Cinnamon Fern belongs to the Royal Fern Family (Osmundaceae), sometimes called the "Flowering Ferns" which is totally misleading since ferns are primitive predecessors to true flowering plants and to seed plants in general (Spermatophyta). In fact, the Osmunda's are among the most primitive of ferns based on the fossil record. The Cinnamon's relationship to other members of the genus is now a subject of debate. Recent genetic studies suggest it should be moved to its own (new) genus, Osmundastrum, (partly borne out by its apparent inability to hybridize), but that would have no effect on our enjoyment of the fern's symmetrical beauty and color. It makes an attractive ornamental if you have a shady, moist spot with acidic soil - and it's deer-proof!

Cinnamon Fern leaves taper to a point at the tip, but only semi-taper toward the base, meaning the narrowing ends abruptly. [For those needing additional identification details, the fronds are "twice-cut," i.e. the leaves are divided into pointed leaflets (called pinnae) which are then deeply lobed but not quite divided into blunt-pointed subleaflets (normally called pinnules). Look for small woolly tufts where the leaflets attach to the main leaf stalk (called the axis or rachis). Technically the stem or stalk (a.k.a. stipe) is the portion between the lowest leaflets and the ground.]

Cinnamon Ferns can be found throughout the eastern portion of the northern hemisphere and its range continues south as far as Paraguay. Surprisingly, it also occurs in eastern Asia from Siberia to Vietnam, but this is considered a separate subspecies.

The local variety is noted on several plant lists from the Adirondacks, such as the Moose River Plains, but I'd be interested in hearing about other locations where you've found it. I have some photos of the fronds turning yellow and then bronze in the fall, and if I remember to locate one of these (from Cranberry Lake? or another location), I'll post it at the end of summer.

Corrections, comments and questions are always welcome by emailing
northeastnaturalist@yahoo.com