. The algae. Algae. 102 THE ALGAE swarmers whose fate is not known although they are probably Fig. 57 Halimeda. A, plant of H. simulans ( x 33). B, H. discoidea, longitudinal section showing structure ( x 20). C. central filament: two fuse and subsequently divide into three ( x 20). D, cuticle of H. opuntia ( x 132-5). E, H. scabra, termination of filaments ( x 100). F, fruiting plant. G, sporangia. (A, D, E, after Taylor^ B, C, after Howe; F, G, after Oltmanns.) * Caulerpaceae: Caulerpa {caul, stem; erpa, creep). Fig. 58 Most of the species frequent the quiet shallow waters of the t
. The algae. Algae. 102 THE ALGAE swarmers whose fate is not known although they are probably Fig. 57 Halimeda. A, plant of H. simulans ( x 33). B, H. discoidea, longitudinal section showing structure ( x 20). C. central filament: two fuse and subsequently divide into three ( x 20). D, cuticle of H. opuntia ( x 132-5). E, H. scabra, termination of filaments ( x 100). F, fruiting plant. G, sporangia. (A, D, E, after Taylor^ B, C, after Howe; F, G, after Oltmanns.) * Caulerpaceae: Caulerpa {caul, stem; erpa, creep). Fig. 58 Most of the species frequent the quiet shallow waters of the tropics where they are often rooted in sand or mud, but two have migrated to become denizens of the Mediterranean. The prostrate rhizome is attached by means of colourless rhizoids and gives rise to numerous, erect, upright assimilatory shoots with apical growth, the form and arrangement of which may vary very considerably (Fig. 58). Radial branching is regarded as primitive, whilst the more evolved forms of quieter waters possess a bilateral branching system. The genus has been divided by Borgesen into three groups: (a) The species of this group, which grow where there is much mud, possess rhizomes that are vertical or oblique, thus enabling them to reach the surface even when covered suc- cessively by mud ( C. verticillata). (h) The rhizome in these species first branches at some distance from its point of origin and it possesses a pointed apex which aids in boring through sand or mud ( C. cupressoides). (c) The rhizome is richly branched immediately from its point of origin and the various species are principally to be found attached to rocks and coral reefs ( C racemosa).. 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
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Keywords: ., bo, bookcentury1900, bookcollectionbiodiversity, booksubjectalgae
