Description
RUSTY WOODSIA, a perennial, usually grows on acidic rocks in Precambrian Shield. Stems compact, erect or ascending, with abundant persistent leaf stalk bases of more or less equal length; scales brown, lanceolate (lance-shaped). Leaves all alike, dying back over winter, 5-25 cm long, 2-3 cm wide. Petiole (leaf stalk) brown to dark purple, breaking off and leaving a persistent base. Leaf blades narrowly lanceolate; pinnate to bipinnate (leaflets or pinnae arranged on either side of an axis or rachis); rachis with abundant hairs and scales. Pinnae ovate-lanceolate to deltate, longer than wide, abruptly tapered to a rounded or broadly acute tip; upper surface with a mixture of hairs and scales, lower surface with hairs concentrated along the midrib. Indusium covering the sorus (group of sporangia) composed of hair-like scales. Sori round, numerous and close together on the underside of the pinnae. Sporangia many, releasing spores in summer-early fall.
Diagnostic Characteristics
Plants on rock. Stems compact, erect. Leaves all the same in appearance, dying back over winter. Petioles jointed at the base, the persistent bases appearing the same length. Blades 1-2 pinnate-pinnatifid, with scales and or hairs on both sides. Sori in 1 row between midrib and margin of pinnae; indusia of narrow hairlike segments, longer than wide, usually surpassing the mature sporangia.