Synonyms: Amphiroa parthenopea Zanardini (1841) p. 42; Amphiroa complanata Kützing (1843) p. 388; Amphiroa exilis Harvey (1847) p. 95; Amphiroa polysona Montagne (1849) p. 136; Amphiroa algeriensis Kützing (1857) 21-t, 44-n, p. 2166.

VEGETATIVE FEATURES

Thallus habit: more or less erect, sometimes bushy. Size: 2-5cm high. Branching: dichotomous, occasionally irregular (A). Intergenicula: tapered towards the base and flattened at the apices (B) (up to 3mm long, lower diameter 0.6-0.65mm, upper diameter 0.4mm) apices characteristically knife-like and striped (B). Genicula: with 2 (3-4) rows of cells (D). Colour of living specimen: pink, pink-violet. Colour of dried specimen: pink-violet to white.


Medulla: 2-3 rows of long cells: 70-90µm long x 12-18µm in diameter with an alternation of 1 row of short cells: 30µm long x 6-12µm in diameter. Cortex: 5-13 rows of oblong cells (8-25µm long). Epithallial cells: 5-14µm in diameter (C). Cell connections: secondary pit-connections. Other features: trichocytes (C) rarely observed.

Conceptacles: lateral, hemispherical, slightly protruding (B-see arrow). Gametangial conceptacles: spermatangial 200-250µm in diameter. Carposporangial conceptacles: warty, 150-200µm in diameter. Tetra/bisporangial conceptacles: 200-250(300)µm in diameter. Distinct paraphyses present. Phenology: May, June.

Habitat: like that of A. rigida, species of sheltered environments. Bathymetric distribution: sublittoral, from surface to 30m deep. Geographic distribution (Babbini & Bressan 1997):

Alboran Sea (A): Morocco, Spain; Western Mediterranean Sea (African shores) (B): Algeria, Tunisia; Middle Western Mediterranean Sea (C): Spain, France; North Western Mediterranean Sea (D): Spain, France, Italy; North Adriatic Sea (E): Croatia; Middle Adriatic Sea (F): Italy, Croatia; South Adriatic Sea (G): Italy; South Eastern Mediterranean Sea (H): Italy, Malta; Middle Eastern Mediterranean Sea (L): Turkey, Syria; North Eastern Mediterranean Sea (M): Turkey.