Osmunda cinnamomea L.
Cinnamon fern
Cinnamon ferns are natives of the Americas, as well as eastern Asia. They date all the way back to the Paleozoic era, somewhere between 500 million and 250 million years ago—they may be the oldest living species. Their longevity is due in part to their prodigious production of spores, estimated at somewhere between 8 and 43 million per plant. Until 2008, these ferns were known as Osmunda cinnamomea.
Identification: Cinnamon ferns produce sterile fronds 12–59″ (30–150 cm) tall and 6–8″ (15–20 cm) wide, with opposing leaflets 1¾–4″ (5–10 cm) long and ¾–⅞″ (2–2.5 cm) wide. The leaflets are so deeply lobed that the fronds appear to be bipinnate. These ferns also produce separate fertile fronds 8–18″ (20–45 cm) tall, and it is the light brown color of these fronds that give the fern its common name. As the plant ages, the fronds darken to brown and almost black. These ferns reproduce by spores as mentioned above, and also by cloning themselves, forming huge clonal groups.
Habitats: Prefers moist, rich, humusy, acidic soils, but adapts to lesser conditions.
Online References:
References:
Osmundastrum cinnamomeum (L.) C. Presl
6/4/2021 · Robert P. Tristram Coffin Wild Flower Reservation, Woolwich, Maine · ≈ 3 × 4½″ (7.5 × 11 cm) 
6/9/2025 · Curtis Farm Preserve, Harpswell, Maine · ≈ 6 × 10″ (16 × 24 cm) 
8/24/2009 · Tom and Susan’s, Pepperell, Massachusetts · ≈ 4½ × 7″ (11 × 17 cm) 
8/24/2009 · Tom and Susan’s, Pepperell, Massachusetts · ≈ 6 × 9″ (14 × 22 cm) 
8/24/2009 · Tom and Susan’s, Pepperell, Massachusetts · ≈ 4½ × 3″ (11 × 7.9 cm) 
6/4/2015 · Flagg Hill Conservation Area, Stow, Massachusetts · ≈ 4½ × 7″ (11 × 17 cm) 
8/24/2009 · Tom and Susan’s, Pepperell, Massachusetts · ≈ 9 × 14″ (23 × 35 cm) 
5/26/2008 · Wachusett Mountain, Princeton, Massachusetts · ≈ 1½ × 2½′ (55 × 82 cm) 
6/4/2015 · Flagg Hill Conservation Area, Stow, Massachusetts · ≈ 4 × 6″ (10 × 15 cm) 
7/4/2025 · Wilson’s Cove, Harpswell, Maine 
6/4/2021 · Robert P. Tristram Coffin Wild Flower Reservation, Woolwich, Maine · ≈ 4 × 6″ (10 × 16 cm) 
5/18/2012 · Mine Falls Park, Nashua, New Hampshire · ≈ 1 × 2′ (41 × 62 cm) 
8/3/2025 · Saco Heath Preserve, Saco, Maine · ≈ 9 × 12″ (22 × 29 cm) 
5/14/2012 · Acton Arboretum, Acton, Massachusetts · ≈ 11 × 7″ (27 × 18 cm) 
5/15/2010 · Garden in the Woods, Framingham, Massachusetts · ≈ 4 × 6″ (10 × 15 cm) 
ID is uncertain 
6/9/2025 · Curtis Farm Preserve, Harpswell, Maine · ≈ 6 × 10″ (16 × 24 cm) 
7/4/2025 · Wilson’s Cove, Harpswell, Maine · ≈ 3 × 2½′ (90 × 73 cm) 
6/4/2021 · Robert P. Tristram Coffin Wild Flower Reservation, Woolwich, Maine · ≈ 6 × 4″ (16 × 10 cm) 
5/28/2021 · Brunswick Commons, Brunswick, Maine · ≈ 4½ × 7″ (11 × 16 cm) 
5/28/2021 · Brunswick Commons, Brunswick, Maine · ≈ 11 × 7″ (28 × 18 cm) 
5/29/2014 · Tom and Susan’s, Pepperell, Massachusetts · ≈ 6 × 9″ (16 × 23 cm) 
5/29/2014 · Tom and Susan’s, Pepperell, Massachusetts · ≈ 6 × 9″ (16 × 23 cm) 
5/30/2014 · Tom and Susan’s, Pepperell, Massachusetts · ≈ 9 × 6″ (22 × 15 cm) 
8/24/2009 · Tom and Susan’s, Pepperell, Massachusetts · ≈ 4½ × 3″ (11 × 7.9 cm) 
5/14/2012 · Acton Arboretum, Acton, Massachusetts · ≈ 6 × 9″ (15 × 23 cm) 
10/2/2023 · Marsh View Loop, Ridgewell Preserve, Phippsburg, Maine 
8/24/2009 · Tom and Susan’s, Pepperell, Massachusetts 
| Kingdom | Plantae | Plants, but not fungi, lichens, or algae (from Stearn's Botanical Latin) |
| Subkingdom | Tracheobionta | Vascular plants—plants with a “circulatory system” for delivering water and nutrients |
| Division | Pteridophyta | Ferns |
| Class | Filicopsida | “Leptosporangiate” (has to do with how their spores form) ferns—includes most ferns |
| Order | Polypodiales | Polypod ferns |
| Family | Osmundaceae | Possibly derives from Osmunder, a Saxon name for the god Thor |
| Genus | Osmunda | Possibly derives from Osmunder, a Saxon name for the god Thor |
| Species | cinnamomea | From the Latin for ”cinnamon,“ the color of the spores |
Osmunda cinnamomea description by Thomas H. Kent, not updated.
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