Life history and reproduction of Botryocladia ardreana sp. nov. (Rhodymeniales, Rhodophyta) from Portugal

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Abstract
Botryocladia ardreana sp. nov. was collected from Portugal, where it has been known as B. boergesenii, and maintained in culture for over 10 years. Plants in culture reach 77 mm in length. They consist of a basal disc or a dichotomously divided basal rhizoidal system that gives rise to upright stipes on which vesicles are borne terminally or laterally. The vesicles, which are 2-4 mm in diam. and up to 70 mm long, are ovate or elongate-cylindrical, and are simple or branched up to five times. Vesicle walls consist of three layers, the outermost of which forms an irregular network over the middle layer. Plants are dioecious. Male plants produce spermatangia in relatively unmodified sori. Female plants produce few carpogonial branches, which are composed of four cells. Gonimoblast development takes place outwards into a cavity formed by stretching of subcortical cells. A tela arachnoidea that persists in the mature cystocarp is formed by this stretching process. Mature cystocarps bulge prominently outwards and have a distinct ostiole and a well developed pericarp. Tetrasporangia are produced by intercalary initials in slightly modified cortical sori, are successively divided and tetraspores are cruciately or slightly irregularly arranged. The occurrence in B. ardreana of a tela arachnoidea in cystocarps that protrude strongly, intrusive cortical filaments, and secretory cells that frequently proliferate casts doubts on the generic distinctions between stalked, vesiculate members of the Rhodymeniaceae. The new species differs from other species of the genus in that secretory cells, which are borne in groups of one to six on rounded or stellate secretory initial cells, often proliferate to form filaments up to three cells long. Polysiphonia-type life history was completed several times in culture. At 15.degree. C, 16:8 h (LD) and 15.degree. C, 8:16 h (SD) carpospores and tetraspores formed tetrasporangial and gametangial plants respectively after 18-20 weeks. A day-length effect on growth or reproduction was not discernible. At 10.degree. C, LD and SD, sporelings grew slowly and formed vesicles, but did not produce reproductive cells. At 5.degree. C, SD, no germination occurred. At 20.degree. C, LD, upright frond and branch production were much more rapid than at 15.degree. C LD or SD: gametangia formed after 42 weeks.