sensitive fern

Onoclea sensibilis, the sensitive fern, also known as the bead fern, is a coarse-textured, medium to large-sized deciduous perennial fern. The name comes from the observation by early American settlers that it was very sensitive to frost, the fronds dying quickly when first touched by it. It is sometimes treated as the only species in Onoclea, but some authors do not consider the genus monotypic.