. The elements of botany embracing organography, histology, vegetable physiology, systematic botany and economic botany ... together with a complete glossary of botanical terms. Botany. ZYGOSPORES. 127 Two small branches from the vegetative threads, or my- celium, unite end to end (Fig. 238,1); continue lo grow larger (Fig. 238, II) ; the terminal portion of each becomes separated by a partition wall (Fig. 238, III) ; the common wall between these cell-ends beeomes absorbed (Fig. 238, IV); their contents fuse; a firm, thick cell-wall is secreted; •and thus is formed the zygospore (Fig. 238, F)
. The elements of botany embracing organography, histology, vegetable physiology, systematic botany and economic botany ... together with a complete glossary of botanical terms. Botany. ZYGOSPORES. 127 Two small branches from the vegetative threads, or my- celium, unite end to end (Fig. 238,1); continue lo grow larger (Fig. 238, II) ; the terminal portion of each becomes separated by a partition wall (Fig. 238, III) ; the common wall between these cell-ends beeomes absorbed (Fig. 238, IV); their contents fuse; a firm, thick cell-wall is secreted; •and thus is formed the zygospore (Fig. 238, F), or rest- ing-spore, as it is sometimes called, for it often remains quiescent and retains its vitality for a great length of time. i6i. The Hydro- dictyon, or Water-net, a fresh-water Alga, is a representative of the division, Zygosporese. It sometimes occurs in abundance in ponds and slow streams. It is composed of a multi- tude of cells, arranged so as to form a tubular net, whose meshes in the full-grown plant—when it may be eight or ten inches long—are plainly visible to the naked eye. It reproduces by the protoplasm of certain cells breaking up into several thousand small masses, or daughter-cells, which presently unite bo as to form a minia- ture net; the wall of the mother-cell beeomes absorbed, and the little plant is set free. It is said also to repro- duce by means of swarm-spores. The Desmids (Desmi- diacece) are motile unicellular fresh-water Algse (Figs. 239, 240), belonging also to this division. The cells are. Fig. 238. Successive stages (/, //, ///, ly, V) in the formation of a zygospore in case of Mucor 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 Kellerman, William Ashbrook, 1850-1908. Philadelphia, J. E. Potter and Company
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1883
