. Plants and their uses; an introduction to botany . 1^^ Fig. 309.—Grape Desmid. A, first stage in conjugation; the two halves ofthe cell-wall {b) have been broken apart by the protruding protoplast(c). B, later stage; the protoplasts of two plants are coming , final stage; the two protoplasts have fused into one mass to form azygospore (/) leaving the old cell-walls (e, h) empty. D, E, F, stagesin the ripening of the zygospore which surrounds itself with a pro-tective wall from which numerous projections finally arise, ^a (De-Bary.) 478 LIFE-HISTORIES the process of fission, by whic
. Plants and their uses; an introduction to botany . 1^^ Fig. 309.—Grape Desmid. A, first stage in conjugation; the two halves ofthe cell-wall {b) have been broken apart by the protruding protoplast(c). B, later stage; the protoplasts of two plants are coming , final stage; the two protoplasts have fused into one mass to form azygospore (/) leaving the old cell-walls (e, h) empty. D, E, F, stagesin the ripening of the zygospore which surrounds itself with a pro-tective wall from which numerous projections finally arise, ^a (De-Bary.) 478 LIFE-HISTORIES the process of fission, by which they multiply under ordinary con-ditions. As shown in Fi^. 308, tlie outer firm layer of the wall,ruptures at the place of constriction, allowing the semicells toseparate, while the protoi^lasm of the isthmus or neck which joinsthem elongates, being still covered by a thin, elastic, inner layer ofcellulose. The nucleus and chromatophores divide, half going toeither end. A partition is then formed across the middle of theisthmus, and the new jxi
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1913
