Delicately membranous, rose-pink fronds with an elongate fan-shaped outline, margins distinctly frilly, to 40 mm or, exceptionally, to 1 m, sessile or shortly stipitate (< 2 mm long). Frond veinless, undivided or deeply subdichotomously divided to the base; apices blunt or rounded, often ribbon-like. Gametophyte plants form rounded spots to 5 mm in diameter whilst tetrasporphyte plants form characteristic elongated spots.

Original publication: Greville, R.K. (1830). Algae britannicae, or descriptions of the marine and other inarticulated plants of the British islands, belonging to the order Algae; with plates illustrative of the genera. pp. [i*-iii*], [i]-lxxxviii, [1]-218, pl. 1-19. Edinburgh & London: McLachlan & Stewart; Baldwin & Cradock.

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Key characteristics: Delicate, veinless, translucent fronds with and elongated fan shape and with elongate or rounded spots (reproductive sori) scattered regularly on most plants. Extremely large plants to 1 m long have been known for many years from NE Ireland; there is no explanation for this phenomenon.

Similar species: Similarly delicate Porphyra species occur mainly in the intertidal but are more gelatinous to the touch and do not form well-defined rounded or elongated spots; Halarachnion ligulatum is less translucent, and is less delicate and not frilly; Haraldiophyllum bonnemaisonii is generally clearly stalked and has reproductive sori that are rounded rather than elongated.

Lin, S.-M., Fredericq, S. & Hommersand, M.H. (2004). Augophyllum, a new genus of the Delesseriaceae (Rhodophyta) based on rbcL sequence analysis and cystocarp development. Journal of Phycology 40: 962-976, 7 figs, 1 table.

Loiseaux-de Goër, S. & Noailles, M.-C. (2008). Algues de Roscoff. pp. [1]-215, col. figs. Roscoff: Editions de la Station Biologique de Roscoff.

Maggs, C.A. & Hommersand, M.H. (1993). Seaweeds of the British Isles. Volume 1. Rhodophyta. Part 3A. Ceramiales. pp. xv + 444, 129 figs, map. London: HMSO.

Papenfuss, G.F. (1964). Catalogue and bibliography of Antarctic and Sub-Antarctic benthic marine algae. In: Bibliography of the Antarctic Seas. (Lee, M.O. Eds) Vol.1, pp. 1-76. Washington D.C.: American Geophysical Union.

Basionym: Fucus punctatus Stackhouse

Type locality: Wemouth, Dorset, England (Withering 1796: 405)