Synoynms: Nullipora trochanter (Bory) nomina rejcienda ICBN (2002), Lithophyllum byssoides (Lamarck) Foslie sensu Hamel & Lemoine (1952) p. 20, Lithophyllum trochanter (Bory) H. Huvé ex Woelkerling (1998) p. 259.

VEGETATIVE FEATURES

Thallus habit: hemispherical cushion-like thalli, bushy, formed by excrescences with annular stripes, sometimes dicotomically ramified (A). Excrescences thin, fragile, erect, arising in all directions, sometimes intermingled. Size: 5cm high, 2-5cm in diameter; maximum diameter of excrescences 1.5 (3)mm. Colour of living specimen: violet with lighter ends. Colour of dried specimen: from violet grey-mauve to white.

Basal crust: multistratose thallus with rectangular, oblique cells (particularly in regeneration tissue). Basal filaments: cells arranged in quite arched rows (B) (100) 120-140 (170)µm long x 6-7µm in diameter. Erect filaments: cells (23) 35-45 (60)µm long x 6-13µm in diameter. Epithallial cells: rounded 6-10µm in diameter (C). Cell connections: secondary pit-connections.

Gametangial conceptacles: slightly raised, outer diameter 400-500(550)µm. Tetra/bisporangial conceptacles: uniporate, conical, slightly raised (D); spread at the base; outer diameter 350-600µm. Phenology: June (to be defined!).

Habitat: encrusting hard bottoms, exposed to waves or currents action in well-lit sites; recorded even in littoral pools. Usually occurring in specific association with Lithophyllum byssoides, Tenarea tortuosa, Neogoniolithon brassica-florida. Bathymetric distribution: littoral, rarely supralittoral. Geographic distribution (Babbini & Bressan 1997):

Western Mediterranean Sea (African shores) (B): Algeria; Middle Western Mediterranean Sea (C): France, Italy; Middle Adriatic Sea (F): Italy, Croatia; South Eastern Mediterranean Sea (H): Italy, Libya, Israel; Middle Eastern Mediterranean Sea (L): Greece, Syria; North Eastern Mediterranean Sea (M): Greece.