Osmundastrum cinnamomeum is a deciduous herbaceous plant that produces separate fertile and sterile fronds.
The sterile fronds are spreading, 30–150 cm (0.98–4.92 ft) tall and 15–20 cm (5.9–7.9 in) broad, pinnate, with pinnae 5–10 cm (2.0–3.9 in) long and 2–2.5 cm (0.79–0.98 in) broad, deeply lobed (so the fronds are nearly, but not quite, bipinnate).
The fertile spore-bearing fronds are erect and shorter, 20–45 cm (7.9–17.7 in) tall; they become cinnamon-colored, which gives the species its name.
The fertile leaves appear first; their green color slowly becomes brown as the season progresses and the spores are dropped.
The spore-bearing stems persist after the sterile fronds are killed by frost, until the next season.
The spores must develop within a few weeks or fail.

The Osmundastrum cinnamomeum fern forms huge clonal colonies in swampy areas.
These ferns form massive rootstocks with densely matted, wiry roots.
This root mass is an excellent substrate for many epiphytal plants.
They are often harvested as osmunda fiber and used horticulturally, especially in propagating and growing orchids.
Cinnamon Ferns do not actually produce cinnamon; they are named for the color of the fertile fronds.
Osmundastrum cinnamomeum is a deciduous herbaceous plant that produces separate fertile and sterile fronds. The sterile fronds are spreading, 30–150 cm (0.98–4.92 ft) tall and 15–20 cm (5.9–7.9 in) broad, pinnate, with pinnae 5–10 cm (2.0–3.9 in) long and 2–2.5 cm (0.79–0.98 in) broad, deeply lobed (so the fronds are nearly, but not quite, bipinnate). The fertile spore-bearing fronds are erect and shorter, 20–45 cm (7.9–17.7 in) tall; they become cinnamon-colored, which gives the species its name. The fertile leaves appear first; their green color slowly becomes brown as the season progresses and the spores are dropped. The spore-bearing stems persist after the sterile fronds are killed by frost, until the next season. The spores must develop within a few weeks or fail.
The Osmundastrum cinnamomeum fern forms huge clonal colonies in swampy areas. These ferns form massive rootstocks with densely matted, wiry roots. This root mass is an excellent substrate for many epiphytal plants. They are often harvested as osmunda fiber and used horticulturally, especially in propagating and growing orchids. Cinnamon Ferns do not actually produce cinnamon; they are named for the color of the fertile fronds.
Osmundastrum