Porphyra inaequicrassa

Thallus blade-like, growing in dense groups, reddish-purple, elongate-oval, widelylanceolate, (8)-9-35 cm long, 2.5-7 cm wide, monostromatic, (17)-21-38(-85) mm thick; sessile, with small disc-like attachment; cordate or rosette-like at base; margins undulate, lobed, entire or sometimes cleft. Cells from surface disordered, roundish, roundish-polygonal, rectangular, (15)-19-22.5×(15)-22.5-31 mm. In transverse section, cells palisadelike, of equal diameter or transversely elongate, 19.5-33×15-56 mm. Cell walls thick, to 12 mm thick, becoming thinner at the margins. Plant dioecious. Spermatangia and gametangia develop along the margins thickening to 70 mm. Growing on sandy-gravel bottom, in shallow bays and epiphytic on Chorda filum, intertidal to upper subtidal (3-5 m deep).

Note: This species has a potential as human food.

Low boreal, Pacific species. Okhotsk Sea, the Sea of Japan.