Wynneophycus geminatus gen. & comb. nov. (Delesseriaceae, Rhodophyta), based on Hypoglossum geminatum Okamura

Wynneophycus gen. nov. (Delesseriaceae, Ceramiales) is a new monotypic genus based on Hypoglossum geminatum Okamura, a species originally described from Japan. Wynneophycus geminatus (Okamura) comb. nov. is characterized by a discoid holdfast, erect or decumbent monostromatic blades with percurrent midribs, production of new blades from the midrib axial cells and absence of microscopic veins. In addition, it has apical cell division, several orders of lateral cell rows and paired transverse periaxial cells and formation of second-order cell rows from lateral cells with all forming third-order cell rows, with the midrib becoming corticated and forming a subterete stipe below as the blade wings are lost. Distinctive features of the new genus include tetrasporangia initiated from and restricted to single rows of second-order cells arranged in a single layer, cover cells developing prior to the tetrasporangia and an absence of intercalary cell divisions. Phylogenetic analyses of rbcL and large-subunit rDNA sequence data support the separation of Wynneophycus from Hypoglossum. We herein report on W. geminatus gen. & comb. nov. and delineate the new tribe Wynneophycuseae within the subfamily Delesserioideae of the family Delesseriaceae.