Phycodrys rubens

Phycodrys rubens is seaweed which is perennial and can grow to 30 cm long and is strongly red in colour.^[1] It grows with flat leaf-like blades which are monostromatic, that is composed of a single flat layer of cells and can grow 3 cm wide. These blades can become 3 cm wide and show a clear mid-rib. The blades have a ruffled margin with veins growing out from the central mid-rib with paired lateral veins. The plants grow from a small disk holdfast with an axis to the blades.^[2][3] The algae are somewhat similar to Delesseria sanguinea which is also strongly red but has a smooth, not dentate, margin.^[2] The shape of the frond is similar to the leaf of an oak tree.^[3]

The gametophytes are dioecious, that is the male and female phases are on separate plants.^[2] The reproductive structures are found at the margins of the blades, the cystocarps as branches attached to the veins^[4] and the tetrasporangial sori occur near the apices of the larger bladelets.^[2]

Commonly found in the littoral, sub-littoral in low rock pools and attached to the stipes of large algae such a Laminaria. Found to a depth 30 m.^[2]

Common on the shores of Ireland, Wales, Isle of Man, Scotland including the Shetland Islands and the north-east and south-east of England. It is not found in the south-east of England.^[5] The species is found in the North Atlantic from Spitzbergen to Portugal and Canada.^[2]

The fronds adhere well to paper and can be dried to make fine specimens.^[3]