Sea Potato

Sea Potato2, Rats Brain

Leathesia difformis2sea potato

Phylum: Phaeophyta2
Family: Chordariaceae2

This is certainly one of the cutest little seaweeds, with an amusing name to match.  I found this sea potato specimen at Acadia National park in a tide pool at Otter Point.  I have also seen sea potato in Scituate, Massachusetts.  They have a large range and are abundant during the summer months2..  It looks like a golden-brown hollow sac1,2  attached to other seaweed as an epiphyte2, and has also been called rat’s brain1..  This specimen is the size of a medium sized marble. The background in this picture is the palm of my hand – whitened by the 50 °F water temperature at Acadia.

Size: 2-3 cm (0.8-1.2 in) 1 other source 7.5-10 cm (3-4 in) 2

Range: Newfoundland to Long Island Sound and parts of North Carolina2


1. Watling, L., Fegley, J., Moring, J., White, S., Sulzer, A. (2003) Life Between the Tides. Tilbury House Pub

2.  Gosner, Keneth L. (1978), Peterson Field Guides: Atlantic Seashore – A field guide to sponges, jellyfish, sea urchins, and more

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Biodiversity Exposed