Polybranchia samanthae has broad, thin, leaf-like cerata with serrated edges. Color of Polybranchia samanthae variies from the green to a light brow. Cerata with finely papillate and often edged with white flecks. Head and rhinophores are tiped with white pigment.
It's a nocturnal species but can be found under rocks during the day. When disturbed can autotomize their central cerata and exude a rubber glue-like mucus.