Umbraulva dangeardii M.J.Wynne & G. Furnari

Cladophora rupestris

Formerly Umbraulva olivascens (P.J.L. Dangeard) G. Furnari, nom. inval.

Description: Thallus sheet-like, olive green, rather stiff and plastic-macintosh-like, to 400 long, often with regular, elliptical holes. Persists throughout the year.
Habitat: on rock in sheltered, but full-salinity areas, often near shellfish farms. Also occurring on marinas in ful salinity.
Distribution: Uncommon but widely distributed in W and S Ireland, Wales, SW England, Netherlands, N France (type locality is Roscoff where it first appeared in a tank in the Station Biologique in the 1930s), south to the Canary Islands; W and E Mediterranean. Some authors (e.g. Brodie, Maggs & John 2004: 106) suggest that this entity may be an introduced species from the W Pacific, which is the only other known location for Umbraulva species, viz, U. amamiensis and U. japonica, and U. dangeardii may be synonymous with one of these.
Key characteristics: olive green colour and rather plasticy feel. Species of Ulva, which it resembles, are more emerald-green in colour.
Photograph: New Quay, Co. Clare, Ireland.

Species list