Algae · Brown algae · Marine Life · South Africa

Lightning seaweed (Oerstedtia scalaris)

Specimen of 'lightning seaweed' on the rocky shores at low tide. Unknown location, South Africa (2021).
Specimen of ‘lightning seaweed’ on the rocky shores at low tide. Unknown location, South Africa (2021).

Plants dark brown to yellowish-brown, with tough rather than rubbery texture, comprising a prominent, woody, conical holdfast bearing one or more main axes that, in turn, bear primary lateral branches with distichous, alternating arrangement of leaves – rarely, second order of lateral branches can be present.
Primary lateral branches slightly compressed at the base, becoming strongly compressed distally and zig-zag in shape, bearing leaves in a bilateral alternative arrangement.

Up to 70 cm tall, with the main axis up to 15 cm long.

Recorded from Cape Agulhas to Durban – not uncommon from Port Alfred to southern KwaZulu-Natal, in the shallow subtidal zone.

Seaweeds of the South African South Coast [Oerstedtia scalaris].

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