Leathesia difformis

Leathesia difformis
Scientific classification
Kingdom:	Chromalveolata
Division:	Heterokontophyta
Class:	Phaeophyceae
Order:	Ectocarpales
Family:	Leathesiaceae
Genus:	Leathesia
Species:	L. difformis
Binomial name
Leathesia difformis (L.) Aresch.

Leathesia difformis, the sea potato, is a littoral brown alga in the class Phaeophyceae and the order Ectocarpales which is commonly attached to other seaweeds and sometimes rocks. When young, the organism is solid but as it matures it become hollow and somewhat convoluted and has the appearance of a small leathery brown bag about the same size as a tennis ball. The texture is rubbery and the outer surface smooth.^{[citation needed]}

These brain-like brown seaweeds can be found growing on rock or as epiphytes on other seaweeds in the mid to low intertidal. Individuals can grow to ~15 cm in diameter. Young individuals can resemble other globular forms of algae. To determine if it is Leathesia, squeeze and flatten a piece between your fingers. Leathesia will break apart into filaments whereas other globular forms will flatten but remain intact