Gelidiophycus hongkongensis, Lin & Liu & Guiry & Jr & Hsueh, 2018

Lin, Showe-Mei, Liu, Li-Chia, Guiry, Michael D., Jr, Put Ang & Hsueh, Hsi-Ju, 2018, A reassessment of Gelidium divaricatum G. Martens (Gelidiaceae, Rhodophyta) from Hong Kong, including Gelidiophycus hongkongensis sp. nov., Phytotaxa 348 (1), pp. 49-55 : 53-54

Gelidiophycus hongkongensis S.-M. Lin & L.-C. Liu, sp. nov. ( Fig. 3 )

Thalli prostrate, mat-forming, attached to the substratum by filamentous haptera, main axes 280–320 μm in diameter, tangled together, laterals irregularly to pinnately branched, lateral branches terete, 220–300 μm in diameter, or flattened, 350–430 μm in width); apices of branches acute to slightly obtuse, growth produced by a single apical cell, cortical cells rounded to oval (3–8 μm by 6–13 μm in diameter), 3–4 celled layers as seen in cross-section; rhizoidal filaments abundant in medulla. Tetrasporangial sori borne on both sides of fertile blades at obtuse or inflated ends of branches, tetrasporangial initials cut off from subcortical cells and fully developed tetrasporangia, 55–62 μm in diameter, with cruciately arranged spores; sexual reproductive structure not found in this study.

Spermatangial sori, 210–310 μm wide by 430–730 μm long, and cystocarps 380–480 μm in diam., and tetrasporangial sori 300–380 μm long by 250–400 μm wide were described by Boo et al. (2013: 1114, as Gelidiophycus divaricatus ).

Holotype:— Hong Kong, Lobster Bay , intertidal zone, 14 Mar. 2017, coll. S.- M. Lin & L.- C. Liu , deposited at Herbarium at Biodiversity Research Center , Academia Sinica, Taipei ( HAST#142344 ) ( Fig. 3A ), isotypes: HAST#142345 , # NTOU 29iii2017 -gh-2 through # NTOU 29iii2017 -gh-21.

Etymology:—The specific epithet refers to the collection locality, Hong Kong.

Distribution:—Only known from Hong Kong.

Phenology:—Tetrasporophytes are commonly found in spring (March through April), and gametophytes were found in April by Boo et al. (2013).

Figures

FIGURE 3. Gelidiophycushongkongensis sp.nov.A, HOLOTYPEhabit before pressing on herbariumpaper,tetrasporic (HAST#142344); B, isotype habit before pressing on herbarium paper, sterile (#NTOU14iii2017-gh-2); C, part of a tetrasporangial thallus showing tetrasporangia branching pattern; D, transverse section througha young branch andshowing rhizoid filament initials issuing from medullary cells (arrows); E, transverse section through a main axis and showing numerous rhizoidal filaments (arrows) surrounding medullary cells; F, tetrasporangial sori borne on swelled, distal ends of branches; G, transverse section through a young tetrasporangia-bearing branch showing tetrasporangial initial (arrowhead) cutting off from an inner cortical cell (white arrow) and elongated tetrasporangia (black arrows); H, close up of cruciately cleaved tetrasporangia, noting that the longitudinal cleavages at upper (large arrows) and lower (small arrows) portions not in the same planes.