. The algae. Algae. EUPHYCOPHYTA 79 Within the Trentepohhaceae there are several genera the species of which form a green discolouration on and in stones and shells of gastropods. Such genera are Gongrosira and Gomontia. These are very difficult to determine taxonomically. They are in need of study as some, at least, may represent stages in the life history of other algae. Recent work on Gomontia polyrhiza has shown that it has a life cycle of a large unicell alternating with a plate-Uke disc. * CoLEOCHAETACEAE: Cokochaete (coleo^ sheath; chaete, hair). Fig. 42 Most of the species are fresh-wa
. The algae. Algae. EUPHYCOPHYTA 79 Within the Trentepohhaceae there are several genera the species of which form a green discolouration on and in stones and shells of gastropods. Such genera are Gongrosira and Gomontia. These are very difficult to determine taxonomically. They are in need of study as some, at least, may represent stages in the life history of other algae. Recent work on Gomontia polyrhiza has shown that it has a life cycle of a large unicell alternating with a plate-Uke disc. * CoLEOCHAETACEAE: Cokochaete (coleo^ sheath; chaete, hair). Fig. 42 Most of the species are fresh-water epiphytes attached to the host by small outgrowths from the basal walls, but there is one species that is endophytic in Nitella, one of the Charales (p. 115).. Fig. 42 Coleochaete. A, C. scutata, thallus with hairs ( x 150). B, C. pulvinata with spermocarp (x 45). C, C pulvinata with antheridia (a) and young carpogonium (c). D, C pulvinata, ahnost mature carpogonium. E, C. pulvinata, fertilized carpogonium, F, C. pulvinata, formation of envelope around fertihzed carpogonium. G, C. pulvinata, mature spermocarp with carpospores. (A, B, after Smith; C-G, after Fritsch.) Some of the species are truly heterotrichous whilst others only possess the prostrate basal portion, which is either composed of loosely branched threads or else is a compact disc. The growth of the erect filaments is by means of the apical cell whilst the basal cushion possesses a marginal meristem. Each cell contains one chloroplast with one or two pyrenoids, and although a character- istic sheathed bristle arises from each cell nevertheless in the old. 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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Keywords: ., bo, bookcentury1900, bookcollectionbiodiversity, booksubjectalgae
