| Genus: |
Ralfsia Berkeley in J.E.Smith & Sowerby |
|
Authority: |
(J.E. Areschoug) J.E. Areschoug |
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Description: |
A Yellowish-brown or dark brow to blackish crust, adhering tightly to rock. Grows in a circular form when young, but becomes irregular and patchy as individuals age and glom together. Crust is 1-2 mm thick. Original publication: Fries, E.M. (1845). Summa vegetabilium Scandinaviae, seu enumeratio, systematica et critica, plantarum tum cotyledonearum, quum nemearum inter mare occidentale et album, inter Eidoram et Nordkap, hactenus lectarum, una cum singulae distributione geographica. pp. Sectio prior: [i], [iii], [i]-258, signatures 1-16 in fours. Holmiae & Lipsiae [Stockholm & Leipzig]: A. Bonnier.  Download PDF from Algaebase
Ralfsia verrucosa, is an olive brown to khaki encrusting brown seaweed that occurs abundantly in low shore tide pools. Here it often forms large, flat, smooth expanses giving the impression that someone had accidentally dropped khaki paint into the tide pools. Ralfsia verrucosa, can occur in high abundance because of its relatively fast growth rate and also because it produces a chemical which seems to deter most grazers. |
| Biogeography |
NE Atlantic (Ireland and Britain to Marocco); SE Atlantic (South Africa); NW Atlantic (Canada, USA); SW Atlantic (Argentina); Mediterranean; Indo-Pacific; Australia. |
| References |
Kain (Jones), J.M. (2008). Winter favours growth and survival of Ralfsia verrucosa (Phaeophyceae) in high intertidal rockpools in southeast Australia. Phycologia 47(5): 498-509, 11 figs, 5 tables. Kain (Jones), J.M., Buchanan, J., Boo, S.M. & Lee, K.M. (2010). Colpomenia bullosa crust masquerading as Ralfsia verrucosa (Phaeophyceae) in southeast Australia. Phycologia 49(6): 617-627. |
| Type information: |
Basionym: Cruoria verrucosa J.E. Areschoug Type locality: Bohuslän, Western Götaland, Sweden (Areschoug 1843: 264).LD Notes: According to Womersley (1987), the type locality is Bahusia, Norway. Syntypes issued as Alg. sc. exs. No 256 |
