. The algae. Algae. Fig. 75 Sphacelaria. A, plant of 5. cirrhosa ( x ^). B, apical cell (a) of 5. cirrhosa. C, 5. cirrhosa, origin of hair (h). a = apical cell. D, hair at older stage; a = apical cell. E, apex of thallus of S. plumigera showing branches, 6; single segment (5), which later divides into upper {us) and lower (Is) segments; a = apical cell. F, origin of branch, h. G, bulbil of S. cirrhosa ( x 52-5). H, unilocular spor- angia, S. racemosa. I, zoospore of 5. bipinnata ( x 1200). J, K, ger- minating spore of 5. bipinnata ( x 1200). (A, original; B-G, after Oltmanns; H, after Taylor;
. The algae. Algae. Fig. 75 Sphacelaria. A, plant of 5. cirrhosa ( x ^). B, apical cell (a) of 5. cirrhosa. C, 5. cirrhosa, origin of hair (h). a = apical cell. D, hair at older stage; a = apical cell. E, apex of thallus of S. plumigera showing branches, 6; single segment (5), which later divides into upper {us) and lower (Is) segments; a = apical cell. F, origin of branch, h. G, bulbil of S. cirrhosa ( x 52-5). H, unilocular spor- angia, S. racemosa. I, zoospore of 5. bipinnata ( x 1200). J, K, ger- minating spore of 5. bipinnata ( x 1200). (A, original; B-G, after Oltmanns; H, after Taylor; I-K, after Papenfuss.) modified branches or propagules which vary in shape from wedge- Uke to di- or triradiate with long or short pedicels. Unilocular and plurilocular sporangia are borne terminally or laterally on simple or branched laterals and are either sessile or shortly pedicellate. The life cycle of Sphacelaria bipinnata has been worked out in some detail and is probably typical of the genus. The asexual generation bears both uni- and plurilocular spor- angia. Zooids from the former fuse in clumps, but those from the latter germinate directly and represent a means of accessory repro- duction. The cytology of the clumps has not been studied though meiosis occurs in the unilocular sporangia. These clumps must give rise to the isomorphic sexual generation which reproduces by means of isogametes liberated from plurilocular sporangia. K 137. 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
