Osmunda cinnamomea is a large fern with a conspicuously
clumped growth form and separate and dramatically different fertile
fronds. The sterile fronds often reach a length of 1 meter in
our area (range 0.3-1.5 meters) with pinnate-pinnatifid blades.
Fertile fronds are shorter
and much narrower than the sterile fronds and when they mature
(mostly in June in the north, perhaps late May in the south) they
change from green to a bright orange-brown color from which the
common name is derived. Once spores have been dispersed the fertile
fronds quickly wilt and fall to the ground where they become quite
inconspicuous. Sterile fronds of O. cinnamomea can be distinguished
by a small area of wooly hairs on the under (abaxial) surface
at the base of the pinnae, that is lacking in the similar O.
claytoniana. Matteuccia struthiopteris is similar in
size, but also lacks the wooly hairs at the pinna base and the
fronds are long tapering at the base with the lowest pinna much
less than half as long as the longest pinnae. O. cinnamomea
is slightly tapered to the base, but the lowest pinnae are more
than half as long as the longest pinnae.
O. cinnamomea is widely distributed in eastern North America,
ranging from Ontario and Minnesota to Texas and east to Florida
and Labrador. It is common throughout Wisconsin in a variety of
at least seasonally wet habitats, often (though not always) with
somewhat acid soils.