. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . Fig. 248. Monoecious species of (, a form of (E. obsoletum Wittr. B, Cleve var. robustum W. & G. S. West. C, (E. Itzigsohnii De Bary var. minor W. West. D, (E. Ahlstrandii Wittr. a, antheridium;oo, oogoniura. All x Fig. 249. Dioecious macrandrous species of(Edogonium. A, male plant of (E. rufescensWittr.; B, female plant of same. C, femaleplant of (E. lautiimniaruiii Wittr.; D, maleplant of same, a, antheridium ; o
. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . Fig. 248. Monoecious species of (, a form of (E. obsoletum Wittr. B, Cleve var. robustum W. & G. S. West. C, (E. Itzigsohnii De Bary var. minor W. West. D, (E. Ahlstrandii Wittr. a, antheridium;oo, oogoniura. All x Fig. 249. Dioecious macrandrous species of(Edogonium. A, male plant of (E. rufescensWittr.; B, female plant of same. C, femaleplant of (E. lautiimniaruiii Wittr.; D, maleplant of same, a, antheridium ; oo, oogo-nium. All x 460. cases, however, the antheridium consists of more than one cell, the antheridialcells arising either by the continued division of the lower daughter-cell or bydivision of the first-formed antheridial cell. The number of cells composing the antheridium is fairly constant for any one species,and in the monoecious species the position of the antheridium relatively to the oogonium isalso a character of specific importance. Sexual reproduction 395 The antherozoids are not always formed in quite the same way. In someof the smaller species of (Edogonium the protoplast of the antheridial cellforms one antherozoid. This is exceptional, as in general two antherozoidsarise in each antheridial cell (fig. 247 C—E). In some species of (Edogonium,especially the dioecious mac
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