Porphyra umbilicalis

Overview

MarLIN describes translucent, tough blades only one cell thick, reaching about 13 by 10 centimetres and turning brownish-purple when dry. They rise from a small, firm disc-shaped holdfast and may form pleated rosettes; one pictured specimen came from Skomer, Wales.

It grows on hard intertidal surfaces and sometimes on other organisms, and is especially common on the upper shore. MarLIN notes abundance on British and Irish rocky coasts but cautions that wider global records need review because of misidentification.

Brawley and colleagues assembled an 87.7-megabase haploid genome with 65.8% G+C and 13,125 gene loci in 2017, relating it to red-algal evolution and to shore stresses of drying, strong light, and shifting temperature and salinity.

Origins & earliest records

MarLIN gives the naming authority Kützing, 1843. This authority date is nomenclatural history, not the evolutionary beginning. One sequenced lineage does not explain the origin of red algae.

Evidence & interpretation

Based on the indexed MarLIN institutional account (Tyler-Walters 2024) and indexed text of Brawley et al.2017 (PNAS).

Selected bibliography

Documented works and useful reading. This is not a list of every appearance.

1. 01

   Tough laver (Porphyra umbilicalis)

   Tyler-Walters · 2024

   Selected bibliography; MarLIN species account.

2. 02

   Insights into the red algae and eukaryotic evolution from the genome of Porphyra umbilicalis (Bangiophyceae, Rhodophyta)

   Brawley et al. · 2017

   Selected bibliography; PNAS 114:E6361–E6370, genome study.

Family, evolution & connections

Taxonomic classification

A hierarchy of classified groups, not a chain of direct ancestors.

Source note: Ranked groups in the NCBI Taxonomy snapshot accessed 7 October 2026; these are not identified direct ancestors. NCBI provides a database classification rather than an independent nomenclatural authority.

1. domainEukaryota
2. phylumRhodophyta
3. classBangiophyceae
4. orderBangiales
5. familyBangiaceae
6. genusPorphyra
7. speciesPorphyra umbilicalis

References

Sources supporting this profile. Linked pages have their own scope and editorial standards.

1. Reference database species pageTough laver (Porphyra umbilicalis)Research access: 2026-10-06
2. Scientific paper (indexed text)Insights into the red algae and eukaryotic evolution from the genome of Porphyra umbilicalis (Bangiophyceae, Rhodophyta)Research access: 2026-10-06
3. Scientific classification referenceNCBI Taxonomy: Porphyra umbilicalisResearch access: 2026-10-07

Image credits

A black silhouette of a broad irregular laver blade with small holes and torn-looking margins.

Attributed silhouette illustration labelled Porphyra umbilicalis by the source; it shows an outline, without colour or diagnostic detail.