Blechnum fluviatile

Rhizome erect and stout, occasionally giving rise to horizontal stolons. Fronds tufted, sterile and fertile fronds dissimilar; sterile fronds 20–75 cm long, soft, forming low rosette; fertile fronds erect. Stipe short, brown, with numerous brown, shiny, narrowly pointed scales. Sterile frond lamina linear, once pinnate, dull mid-green; rachis with many coarse, linear, brown, shiny scales and numerous very small hairs; pinnae short, oval to oblong, mostly sessile but the lowermost shortly stalked or narrowed at base, margins shallowly crenulate, tips rounded. Fertile fronds with pinnae short, linear-oblong, almost parallel to rachis. Sori covering underside of lamina on each side of midvein.