English: Oblong woodsia; Rusty woodsia; Rusty cliff fern.
Synonym: Acrostichum ilvense.
Region: North America, eastern United States; northern Eurasia, Scandinavia, Ural and Altai mountains; Japan, Alaska, Canada, coastal Greenland; Alps.
Habitat: sunny, exposed cliffs, rocky slopes; thin, dry, acidic soils.
Ecology threatened.
BotanyFern.
Leaves: 15 cm long, 3 cm wide; with stiff, erected pointed tips; 12 nearly opposite stemless leaflet; underside of the leaves are covered in white woolly fibres, which later turn rusty brown.