Osmundea osmunda (Hudson) K.W. Nam & Maggs
Also known as Laurencia osmunda (Hudson) Maggs & Hommersand
Common names: Pepper Dulse; Míobhán (Irish)
Description: Cartilaginous, usually markedly compressed, dark purplish-brown to pale yellow fronds, to 100 mm or more long, from a discoid holdfast. Very variable in size and form. Main axis usually simple, branching alternate distichous, repeatedly pinnate. Ultimate ramuli short, blunt.
Habitat: On rocks, perennial, throughout intertidal, often as flattened rosettes covering exposed rocks, also subtidal, generally distributed, abundant.
Similar species: Osmundea pinnatifida is very similar but arises from spreading stolons, which frequently become interlaced and turf-forming. Osmundea truncata has a discoid holdfast, but is less common, generally grows epiphytically, and very rapidly degenerates on collection.
Key characteristics: Discoid holdfast, plants generally attaining large sized, and lowe on the shore.