Sensitive Fern - Bead Fern
Onoclea sensibilis - Linnaeus
Onocleaceae (Sensitive Fern) Family

The Sensitive fern is a coarse-textured, medium to large-sized deciduous perennial fern. The name comes from early American settlers who saw that it was very sensitive to frost, the fronds dying quickly after the first frost. It is sometimes treated as the only species in its family group, but some authorities do not consider the genus as containing only one species.

The sterile and fertile fronds of Onoclea sensibilis are quite different from other ferns. The bright, yellow-green sterile fronds are deeply pinnatifid and are typically borne at intervals along a creeping rhizome. They grow to about 35 inches, with a long, smooth stipe. The fertile fronds are much smaller, non-green, and have very narrow pinnae. The spores are clustered like beads or grapes on the upright fertile fronds, hence the common name Bead fern. The fiddleheads are a pale red color.

The Sensitive fern has a wide distribution in North America, dwelling in wet swamp and wood habitats: wet meadows, thickets and bogs, as well as stream and riverbanks and roadside ditches. It ranges from Newfoundland south to Florida and west to Texas, the Rocky Mountains, North Dakota, Quebec, and Manitoba. It is also native to East Asia, and has become naturalized in western Europe.

It grows best in a shaded or partially shaded area in a moist soil. The plant can tolerate dryer conditions in shade, and will tolerate wet soils and so occurs in soggy ground or at the very edge of water in shade or sun. Sensitive ferns spread to form colonies and are often the first species to inhabit disturbed areas. They can become weedy if not sited properly.

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