. Elementary botany. Botany. while the other chroniosonie of eacli pair goes to the opposite pole. The chromosomes here unite to form the daughter nuclei. Kach of these nuclei now divide as shown in figure 409 (whether the chromo- somes in this second divi- sion in tlie mother cell split longitudinallv or divide transverselv has not been Fig. 40S. definitely settled 1, and four nifferent stages in the separation of divided nutdei are formed in the L'-snaped cnroniosoines at the nuclear plate. (Alter Mottier) In podophyllum. pollen mother cell. The protopjlasm about each one of these four nucle
. Elementary botany. Botany. while the other chroniosonie of eacli pair goes to the opposite pole. The chromosomes here unite to form the daughter nuclei. Kach of these nuclei now divide as shown in figure 409 (whether the chromo- somes in this second divi- sion in tlie mother cell split longitudinallv or divide transverselv has not been Fig. 40S. definitely settled 1, and four nifferent stages in the separation of divided nutdei are formed in the L'-snaped cnroniosoines at the nuclear plate. (Alter Mottier) In podophyllum. pollen mother cell. The protopjlasm about each one of these four nuclei now surrounds itself with a wall and the spores are formed. The number of chromosomes usually the same in a given species throughout one phase of the plant.—In those plants which have been carefully studied, the number of chromosomes in the dividing nucleus has been found to be fairly constant in a given species, through all the divisions in that stage or phase of the plant, especially in the embryonic, or young growing parts. For example, in the prothallium, or gameto phyte, of certain ferns, as osmunda, the nmnber of chromosomes in the di\id ing nucleus is always twelve So in the de\elopment of the pollen of liliuui from the mother cells, and in the divisions of the anthend cell to form the generati\ e cells or sperm cells, there. Fig. 409. Second di\"ision Fig. 410. Chromosomes uniting are always twelve chromo-°^^^i7 "\ p^V .""n^''^" ^* P9ies to form the ;^ c _, c e 1 1 of podophyllum, nuclei of the four spores. somes so far as has been ch™mosomes at poles. (After Mottier.) found. In the development of the egg of lilium from the macrospore there are also twelve 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 Atkinson, George Francis, 1854-1918. New
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