Dictyopteris polypodioides (A.P. de Candolle) J.V. Lamouroux
Also known as Dictyopteris membranacea (Stackhouse) Batters
Description: Thallus flat and leaf-like, to 300 mm long and 20-30 mm broad; fronds olive to yellow-brown, translucent, and ± regularly dichotomously forked with a prominent midrib extending to the apices. Margins sometimes split to the midrib. Initially with an unpleasant smell shortly after collection, and degenerating quickly.
Habitat: large pools at low water and shallow subtidal (above).
Distribution: Widely distributed and locally abundantin summer. All around Ireland except for E coast, W Scotland, Wales, SW England, and S to Portugal and W Africa.
Key characteristics: Midrib, strong smell.
Photographs © M.D. Guiry