Lithophyllum subplicatum (Foslie) Basso & Caragnano & Gall & Rodondi, 2015

Basso, Daniela, Caragnano, Annalisa, Gall, Line Le & Rodondi, Graziella, 2015, The genus Lithophyllum in the north-western Indian Ocean, with description of L. yemenense sp. nov., L. socotraense sp. nov., L. subplicatum comb. et stat. nov., and the resumed L. affine, L. kaiseri, and L. subreduncum (Rhodophyta, Corallinales), Phytotaxa 208 (3), pp. 183-200 : 190-191

Lithophyllum subplicatum (Foslie) comb. et stat. nov.

Figures 6–7 ; Table 3

BASIONYM: Lithophyllum okamurae forma subplicatum Foslie 1901a (K. Norske Vid. Selsk. Skr.: 18) ( Woelkerling et al. 2005: 173).

NOMENCLATURAL SYNONYM: L. kaiseri ? f. subplicata Foslie (1903) , L. kotschyanum f. subplicatum Silva in Silva et al. (1996, p. 248) ( Woelkerling et al. 2005).

LECTOTYPE: TRH, A20-1286 , includes slide 596 ( Fig. 6 ) (Woelkerling 1993: 212).

ETYMOLOGY: the specific epithet means “begged for”.

ILLUSTRATIONS OF TYPE MATERIAL: Printz 1929: pl. 65, fig. 3.

TYPE LOCALITY: Samoa Islands, no collector and date given; ex Botanical Museum Hamburg (Woelkerling 1993; Woelkerling et al. 2005).

MATERIAL EXAMINED: Pacific Ocean, Samoa Islands, the lectotype TRH A 20-1286.

HABITAT AND PHENOLOGY: unknown.

GEOGRAPHIC DISTRIBUTION: L. subplicatum is known only from the type locality, Samoa Islands. Other entries need verification ( Table 1).

HABIT AND VEGETATIVE STRUCTURE: Plants non-endophytic, with fruticose growth-form. The long protuberances are cylindrical and dichotomously branched, diverging, about 3–4 mm in diameter, flattened and anastomosing at their tips. The plant is 7 cm high and 11 cm in diameter ( Fig. 6C ).

Plant structure pseudoparenchymatous ( Fig. 7A–B ). Basal or ventral layer (= hypothallium) dimerous ( Fig. 7B ). Hypothallial cells 20–23 μm long and 12–20 μm in diameter ( Tab. 3). Peripheral region (= perithallium) composed of filaments of cells curving outwards toward the thallus surface, 15–28 μm long and 10–18 μm in diameter ( Fig. 7B ). Cells of adjacent filaments joined by secondary pit connections, cell fusions not observed. Palisade cells not observed. Single trichocytes 30–53 μm long and about 12–15 μm in diameter, abundantly distributed in the perithallium and at the thallus surface ( Fig. 7C ). Single epithallial cells flattened, about 10–13 μm in diameter and 2–3 μm long ( Tab. 3).

REPRODUCTION: Uniporate conceptacle chambers, presumed tetra- or bisporangial, protruding over the surrounding thallus surface, becoming buried in the thallus, 330–360 μm in diameter and 100–170 μm high, with pore-canal 80–110 μm long ( Fig. 7D ; Tab. 3). Floor of the conceptacle chamber convex upward below a central columella. The conceptacle chamber floor is 13–15 cells below the thallus surface. Roof filaments 6–8 cells long, including the terminal epithallial cell ( Fig. 7D ; Tab. 3). Gametangial and carposporangial conceptacles unknown.

REPRESENTATIVE SEQUENCE: KP696792 (LSU).

Figures

FIGURE 6. The lectotype collection of Lithophyllum subplicatum (Foslie) comb. et stat. nov. in TRH.A) Box A20-1286 in TRH. B) Thin section 596 part of the lectotype of L. subplicatum. C) The specimen A20-1286 in TRH, lectotype of L. subplicatum.

FIGURE 7. Microscopical anatomy of the lectotype of L. subplicatum (Foslie) comb. et stat. nov. TRH A20-1286 from decalcified material. A) Trichocytes (arrows) in the perithallus (p) with filaments terminating in flattened epithallial cells (e), slide A20-1286_5. B) Same as inA. Thallus dimerous, with hypothallial (ventral) cells visible on bottom left (h), each one giving rise to a filament of perithallial cells (p). C) Same as in A, with magnification of secondary pit-connections (arrow) and trichocytes (t). D)An empty uniporate conceptacle chamber with 6–8 cells in the roof filaments. Slide A20-1286_5.