FIG. 4 in Lithophyllum artabricum V.Peña, sp. nov. (Corallinales, Rhodophyta): a cryptic species in the Atlantic Iberian Peninsula hitherto assigned to Lithophyllum stictiforme (Areschoug) Hauck

FIG. 4. — Morpho-anatomy of Lithophyllum artabricum V.Peña, sp. nov.: A, B, vertical section of the thallus showing a monomerous thallus construction with non-coaxial medulla; C, vertical section of the thallus showing cortical cells disposed in filaments laterally aligned; D, vertical section of the thallus showing a monomerous thallus construction with coaxial medulla, and a tetra/bisporangial uniporate conceptacle empty and buried; E, F, Vertical section of the thallus showing secondary pit-connections between contiguous filaments of cortical cells (arrows) and epithallial cells flattened disposed in 1-2 layers (arrowheads), G, surface view of the thallus showing polygonal epithallial cells; H, I, surface view of two different development stages of tetra/bisporangial uniporate conceptacles showing the pore flush with thallus surface (arrows). A, H, SANT-Algae 11671; B, C, holotype SANT-Algae 33667; D, E, SANT-Algae 26900; F, SANT-Algae 7046; G, SANT-Algae 11683; I, SANT-Algae 15006. Scale bars: A, B, D, 200 µm; C, G-I, 50 µm; E, F, 20 µm.