Lithophyllum subreduncum Foslie 1901b: 10

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 : 191-193

Lithophyllum subreduncum Foslie 1901b: 10

Figures 8–9 ; Table 3

NOMENCLATURAL SYNONYM: L. kotschyanum f. subredunca Foslie.

HOLOTYPE: TRH, A20-1291 , includes slide 503, ex Herb. W. G. Farlow no. XXXI ( Woelkerling et al. 2005: 174); Fig. 8.

ETYMOLOGY: the specific epithet means “more or less hooked”.

ILLUSTRATIONS OF TYPE MATERIAL: Printz 1929: pl. 65, fig. 12 (as L. kotschyanum f. subredunca ).

TYPE LOCALITY: Sandwich Islands, Hawaii, collector and date unknown (Woelkerling 1993; Woelkerling et al. 2005).

MATERIAL EXAMINED: Pacific Ocean, Sandwich Islands, the holotype TRH A 20-1291.

HABITAT AND PHENOLOGY: unknown.

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

HABIT AND VEGETATIVE STRUCTURE: Plants non-endophytic, with fruticose growth-form. The protuberances are cylindrical and branched, about 4 mm in diameter, up to 14 mm long, irregularly flattened and anastomosing at their tips ( Fig. 8D ). Plant structure pseudoparenchymatous ( Fig. 9A ). Basal or ventral layer (= hypothallium) dimerous. Hypothallial cells 20–23 μm long and 12–15 μm in diameter ( Tab. 3). Peripheral region (= perithallium) composed of filaments of cells curving outwards toward the thallus surface, 20–24 μm long and 12–15 μm in diameter ( Fig. 9A–C ). Cells of adjacent filaments joined by secondary pit connections, cell fusions not observed. Palisade cells not observed. Single trichocytes 27–33 μm long and about 12–15 μm in diameter, abundantly distributed in the perithallium and at the thallus surface ( Fig. 9A–B ). Single epithallial cells flattened, about 10–13 μm in diameter and 2–4 μm long ( Fig. 9C ).

REPRODUCTION: Uniporate conceptacle chambers, presumed tetrasporangial, weakly protruding over the surrounding thallus surface, becoming buried in the thallus, 330 μm in diameter and 130 μm high, with pore-canal 80 μm long ( Fig. 9D ; Tab. 3). Floor of the conceptacle chamber convex upward below a central columella. The conceptacle chamber floor is 15–16 cells below the thallus surface. Roof filaments 5 cells long, including the terminal epithallial cell ( Fig. 9D ; Tab. 3). Gametangial and carposporangial conceptacles unknown.

REPRESENTATIVE SEQUENCE: KP696788 (LSU).

Figures

FIGURE 8. The holotype collection of Lithophyllum subreduncum Foslie in TRH.A) BoxA20-1291 in TRH.B) The carton box containing the holotype of L. subreduncum. C) Thin section 503 part of the holotype of L. subplicatum. D) The specimen A20-1291 in TRH, holotype of L. subreduncum.

FIGURE 9. Microscopical anatomy of the holotype of L. subreduncum Foslie, slide A20-1291_2. A) Vegetative thallus with abundant trichocytes (t) in the perithallus (p), and epithallial flattened cells (e). B) Details of the secondary pit-connections (arrow) in the perithallus and the abundant trichocytes (t). C) Magnification of secondary pit-connections (arrow) and epithallial cells (e). D) A tetrasporangial conceptacle with remain of a central columella.