. A handbook of cryptogamic botany. Cryptogams. 274 ALGJ£. Fk;. 243.— I'., upper, Cladopkora grizcilis Ktz. a, natural size ; c, lower portion (x 200). (After Hauck.) genera, vegetative propagation takes place by means of resting- spores or cysts, usually found in swollen barrel-shaped cells. In Conferva the resting-cells may be either akinetes or apla- nospores; and Wille believes that they are produced espe- cially under circumstances un- favourable for the formation of zoospores. The resting-spores of Confervaceffi are formed in three different ways: either (i) by rejuvenescence, and the fo
. A handbook of cryptogamic botany. Cryptogams. 274 ALGJ£. Fk;. 243.— I'., upper, Cladopkora grizcilis Ktz. a, natural size ; c, lower portion (x 200). (After Hauck.) genera, vegetative propagation takes place by means of resting- spores or cysts, usually found in swollen barrel-shaped cells. In Conferva the resting-cells may be either akinetes or apla- nospores; and Wille believes that they are produced espe- cially under circumstances un- favourable for the formation of zoospores. The resting-spores of Confervaceffi are formed in three different ways: either (i) by rejuvenescence, and the for- mation of a new cell-wall round the contracting contents; or (2) by separation of a portion of the cell-substance so as to form a swollen part of the mother-cell, and the thickening of the cell- wall at this portion; or (3) by the simple thickening of the wall of the mother-cell. In the formation of aplanospores, one, two, or four proceed from a single cell by the cell-contents rounding off and enclosing themselves in a cell-wall while still within the parent-cell. They hibernate within the parent-cell, and germinate in the spring. Resting swarm - cells, naked masses of protoplasm endowed with an amoeboid power of mo- tion, are formed in the same way. The mucilaginous sheath of the Confervacese appears to have the same construction as in the classes of algse already described, but is often but feebly developed. Wille states that the. 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 Bennett, Alfred W. (Alfred William), 1833-1902; Murray, George Robert Milne, 1858-. London, New York, Longmans, Green, and Co.
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