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DescriptionThis native perennial fern consists of a single sterile leaf and a single fertile leaf that bears the spores; the latter is not always produced. The sterile leaf and fertile leaf (if present) are joined together at the base of their stalks; this typically occurs close to the ground. The blade of the sterile leaf is bipinnate-pinnatifid or tripinnate-pinnatifid in its structure; it spans up to 8" long and 8" across. This blade is divided into 1-3 major divisions; each division has a deltoid shape in outline, a bipinnate-pinnatifid structure, and a short stalk at its base. Each major division of the sterile leaf has up to 7 pairs of leaflets; the lower leaflets are stalked, while the upper leaflets are sessile. The lower leaflets and some of the upper leaflets are divided into up to 7 pairs of subleaflets that are oval to oblong-lanceolate in shape; usually the terminal subleaflets are more elongated than the lateral subleaflets. The subleaflets and undivided upper leaflets have finely serrated or crenate margins; sometimes they are irregularly cleft into smaller lobes. The sterile leaf blade is evergreen; it is medium green during the summer, but becomes bronze-colored during the winter (hence the common name). The stalk of the sterile blade is 3-8" long and slightly succulent; both the sterile blade and its stalk are hairless. The fertile leaf blade has a very different appearance from the sterile blade; this blade has a bipinnate or tripinnate structure, but it is contracted into sporangia-bearing branches. The fertile leaf blade is up to 10" tall and 5" across; it is initially light green, but later becomes yellow or brown. The branches of the fertile blade bear dense rows of small globoid sporangia; during the fall or winter, the latter split open to release their minute spores to the wind. The root system consists of fibrous roots that are fleshy and shallow; occasionally, vegetative offsets develop from spreading rhizomes.