. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . is not improbable, however, that this articu-lation is only apparent, as in Aphanochsete, and that the bristles are nottruly septate. Lambert found that the bristles attained a length of45 mm. The most curious species of the genus is C. Nitellarwm Jost (95;Lewis, 07), which is endophytic in the outer layers of the wall of speciesof Nitella. In consequence of its habit the cells are greatly flattened withthin cell-walls; they are also of a muc
. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . is not improbable, however, that this articu-lation is only apparent, as in Aphanochsete, and that the bristles are nottruly septate. Lambert found that the bristles attained a length of45 mm. The most curious species of the genus is C. Nitellarwm Jost (95;Lewis, 07), which is endophytic in the outer layers of the wall of speciesof Nitella. In consequence of its habit the cells are greatly flattened withthin cell-walls; they are also of a much more irregular shape than those ofany other species of the genus. 316 Ulotrichales Each cell possesses one nucleus, and a single parietal chloroplast withone or, more rarely, two pyrenoids. Asexual reproduction takes place by means of large ovoid zoogonidia,which are biciliated, without stigma, and with a large parietal arise singly from the cells of the thallus, more especially from theterminal cells of the branches, and they generally escape from the mother-cell by a circular orifice. On coming to rest the zoogonidia germinate. Fig. 208. Coleocheete pulvinata A. Br. 1, young zoogouidangium (?) ; 2 and 3, youug antheridia(«) and oogoniuni (o); 4, oogonimn (o) just before the opening of the trichogyne and emptyantheridium (a) ; 5, oogonium (o) after opening; 6, zygote still with distinct male (sk) andfemale (ek) nuclei; 7, zygote which has become surrounded by the spermocarp ; 8, thedivisions of the hypnozygote (or oospore after a period of rest). In the vegetative cells infig. 7: k, nucleus; chr, chloroplast; py, pyrenoid. (After Oltmanns.) directly into new plants; those of C. Nitellarum penetrate between thelamellse of the wall of Nitella. The first division of the quiescent zoogonidiumresults in a dorsal and a ventral cell and the disc is developed from theventral cell. The sexual reproduction is of a high type. The sexual organs areoogonia and ant
Size: 1578px × 1584px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambridgeengtheuni
