Synonyms: Lithothamnium corallioides f. minuta Foslie (1899) p. 7; Lithothamnium fruticulosum f. soluta Foslie (1905) p. 7; Lithothamnium solutum f. effusa Foslie (1906) p. 14; Lithothamnium solutum Foslie (1908) p. 214; Lithophyllum solutum (Foslie) Lemoine (1915) p. 13.

VEGETATIVE FEATURES

Thallus habit: encrusting to branched, common as free-living branchlets or as nodules overlaying the substratum (shells or biogenic remains). Uniform margin, adherent or just lobed edge. Size: total diameter up to 1.5-2 (5)cm (branches diameter up to 2mm), 0.06-0.12mm thick. Colour of living specimen: bright pink. Colour of dried specimen: from white to dark grey.

Medulla: not coaxial, dense tissue 5-6 cellular layers (40 (70)µm thick); rectangular cells: (15) 20-25 (30)µm long x 7-12µm in diameter. Cortex: multilayered; fusiform rectangular cells: 25µm long x 5-8µm in diameter. Epithallial cells: numerous layers of flattened and flared cells (A). Cell connections: numerous cell fusions (B).

Gametangial conceptacles: spermatangial not raised, ovoidal, flattened, 360µm diameter x 150µm high; carpogonial raised ovoidal flattened (C), 250-280µm diameter x 100-120µm high. Tetra/bisporangial conceptacles: multiporate, immersed, 300-400µm diameter (very rare). Old conceptacles become buried in the thallus. Phenology: during all year long.

Habitat: on mobile substrata with strong currents; often in association with Phymatolithon calcareum. Bathymetric distribution: lower sublittoral. Geographic distribution (Babbini & Bressan 1997):

Middle Western Mediterranean Sea (C): Spain, France, Italy; North Western Mediterranean Sea (D): Spain, France, Italy; North Adriatic Sea (E): Italy, Croatia; Middle Adriatic Sea (F): Italy, Croatia; South Adriatic Sea (G): Italy; South Eastern Mediterranean Sea (H): Italy, Malta, Tunisia, Libya; Middle Eastern Mediterranean Sea (L): Greece; North Eastern Mediterranean Sea (M): Greece.