Ericaria giacconei sp. nov. (Sargassaceae, Fucophyceae), the species to which the invalidly published Cystoseira hyblaea Giaccone should be referred Author Serio, Donatella Author Furnari, Giovanni Department of Biological, Geological and Environmental Sciences, Section Vegetal Biology, University of Catania, via Empedocle 58, 95128 Catania (Italy) d. serio @ unict. it (corresponding author) serio@unict.it text Cryptogamie, Bryologie 2021 2021-07-07 20 10 141 151 http://dx.doi.org/10.5252/cryptogamie-algologie2021v42a10 journal article 10.5252/cryptogamie-algologie2021v42a10 1776-0992 7819211 Ericaria giacconei Serio & G.Furnari , sp. nov. ( Figs 2-5 ) Thalli caespitose, attached to the substrate by a robust and compact basal disc ( 3-5 cm in diameter) from which 4-20 cauloids, cylindrical, up to 30 cm high and 3-5 mm in diameter, arise; apex of cauloids smooth, not prominent, never surrounded by spiniform appendages, sometimes surrounded by short cylindrical non-spiny young primary branches; primary branches cylindrical, bearing branches of higher order cylindrical, and with subequal development that give the thallus a cupressoid habit; tophules and aerocysts absent; in cross section, medulla formed by small rounded cells, cortex made of roundish cells with thin walls and meristoderm formed by a layer of rectangular cells twice longer than wide; receptacles terminal, cylindrical-ovoid to clavate, 0.5-1 cm long and 1-2 mm wide, with grouped conceptacles; conceptacles bisexual, subspherical, located at the base of spinous deciduous appendages; oogonia occupying the floor of the conceptacle and antheridia on branched hairs. HOLOTYPE . — Italy , Straits of Sicily , Porto Palo di Capo Passero , Contrada Guardiana , 36°39’03”N , 15°04’37”E , 0.50 m depth , 11.I.2020 , fertile specimen, coll. Serio , ( CAT [ CAT 2716 ] ( Figs 3 , 4 ). ISOTYPE. — Same data of the holotype ; CAT [ CAT 2717, CAT 2718]). E TYMOLOGY. — The specific epithet honours Professor Giuseppe Giaccone, who first found this species, for his significant contributions to the study of the Cystoseira complex. TYPE LOCALITY . — Porto Palo di Capo Passero ( Sicily , Italy ), 36°39’03”N , 15°04’37”E . DISTRIBUTION. — Type locality; Punta D’Aliga ( Sicily , Italy ) ( Giaccone 1986 as C. hyblaea ); Isola delle Correnti ( Sicily , Italy ) ( Pizzuto 1999 as C. crinita ); Kelibia ( Tunisia ) ( Bouafif et al. 2016 as C. hyblaea ) ( Fig. 1 ). HABITAT. — Plants living on semi-exposed rocky shores at 0.2- 1.0 m depth. Species vicariant of E. amentacea ( Giaccone, 1986 as C. amentacea ). REMARKS Other figures (as “ C. hyblaea ” ): Giaccone (1986 , figs 1, 2), Cormaci et al. (2012 , pl. 111, figs 1-3), Bouafif et al. (2016 , figs 21-24).