Comprehensive Description

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Description

This perennial fern consists of either individual leaves or small tufts of simple-pinnate leaves. Individual leaves are ½–1½' long and 1-2" across; the semi-evergreen fertile leaves are longer and more erect than the evergreen sterile leaves. Each compound leaf has 10-40 pairs of leaflets along its rachis (or central stalk); these leaflets are usually arranged alternately along the rachis, rather than in opposite pairs. The leaflets toward the top and the bottom of each leaf are smaller in size than those toward the middle. Both the rachis and petiole of mature leaves are terete and dark purplish brown; usually they are glabrous, but sometimes sparse white hairs are present. For very young leaves emerging from the ground, the rachis and petiole can be light green. Individual petioles (about 1-4" long) are much shorter than the leaf blades. The medium to dark green leaflets are deltate-oblong or deltate-elliptic in shape, crenate or crenate-serrate along their margins, and glabrous; young leaflets often have a lustrous quality. The leaflets are basally auricled (with eared lobes) on their upper sides, providing them with an asymmetrical appearance; these narrowly deltate auricles overlap the rachis. The leaflets are pinnately veined; each one has a central vein and several lateral veins. The lateral veins are forked. On mature fertile leaves, the leaflets develop two columns of elongated sori (spore-bearing structures) on their undersides; these sori are oriented diagonally to the central veins of the leaflets. Attached along one side of each sorus, there is an elongated indusium (protective membrane) that eventually withers away. The spores are released to the wind during the summer or early fall. The root system consists of a short rhizome with fibrous roots; relative to the ground surface, the position of this rhizome is often vertical or diagonal in its orientation. Cultivation

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© John Hilty

Source: Illinois Wildflowers

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