Polyneura bonnemaisoniae (C. Agardh) Maggs & Hommersand
Also known as Polyneura hilliae (Greville) Kylin
Description: Thick, soft, deep crimson to rose fronds, turning orange in fresh water. Fronds translucent, flattened, fan-shaped, to 300 mm long (above, a large plant collected in March). Stipe to 6 mm long, from flattened discoid base. Blade simple to deeply cleft into wedge- or ribbon-shaped segments, margin proliferous, undulate. Venation palmate, no distinct midrib, veins anastomosing. Microscopic veins present in younger parts.
Habitat: On rock at extreme low water, occasionally on Laminaria hyperborea stipes, spring and summer, widely distributed but commoner on southern and south-western shores.