Osmundea pinnatifida (Hudson) Stackhouse
Also known as Laurencia pinnatifida (Hudson) J.V. Lamouroux
Common names: Pepper Dulse; Míobhán (Irish).
Description: Cartilaginous, usually markedly compressed, blackish-purple bleaching to pale yellow fronds, usually 20-80 mm long, forming extensive, closely interwoven turfs from entangled stolonous holfasts. 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 osmunda is very similar but arises from a discoid holdfast, and is generally lower down on the shore and larger, with isolated plants. Osmundea truncata is much less common, is more pinnately branched, generally grows epiphytically, and rapidly degenerates on collection.
Key characteristics: Stoloniferous holdfast, smaller than Osmundea osmunda , and less profically branched.