. The algae. Algae. EUPHYCOPHYTA 141 known. They would appear to represent a transition from the Ecto- carpalean type to the Dictyotalean type of reproduction, though retaining Ectocarpalean morphology. Asexual reproduction takes place by means of characteristic, large, motionless quadrinucleate monospores which almost certainly represent unsegmented or primitive tetraspores. Sexual fusion has not so far been reported within the order. Recent work (Kornmann, 1953) has shown that the genus Acinetospora^ formerly placed in this order, is properly a member of the Ectocarpales. Tilopteridaceae: Ha
. The algae. Algae. EUPHYCOPHYTA 141 known. They would appear to represent a transition from the Ecto- carpalean type to the Dictyotalean type of reproduction, though retaining Ectocarpalean morphology. Asexual reproduction takes place by means of characteristic, large, motionless quadrinucleate monospores which almost certainly represent unsegmented or primitive tetraspores. Sexual fusion has not so far been reported within the order. Recent work (Kornmann, 1953) has shown that the genus Acinetospora^ formerly placed in this order, is properly a member of the Ectocarpales. Tilopteridaceae: Haplospora {haplo, simple; spora, seed). Fig. 78 The plants, which arise from a basal disc, are filamentous, with irregular pinnate branching from the main axes. The lower portion becomes multiseriate by septation and then resembles Sphacelaria but the growth is always intercalary. The sexual plants develop intercalary, tubular, plurilocular gametangia which are produced by the transformation of one or more cells of the main Fig. 78 Haplospora globosa. A, portion of plant with uninucleate sporangia, m (oogonia?), and plurilocular microgametangia, p. B, plurilocular microgametangium. C, monosporangium with quadrinucleate monospore. D, monosporangia. E, F, unilocular sporangia (oogonia?). (A-Q after Oltmanns, D-F, after Tilden.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Chapman, V. J. (Valentine Jackson), 1910-. London, Macmillan; New York, St. Martin's Press
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Photo credit: © Library Book Collection / Alamy / Afripics
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Keywords: ., bo, bookcentury1900, bookcollectionbiodiversity, booksubjectalgae
