. Nature and development of plants. Botany. 172 REPRODUCTION OF DIATOMS method of reproduction is termed sexual reproduction. The two fusing cells are looked upon as male and female cells or gametes, although in these simple plants there is no indication of sex that would enable us to recognize them as such. In the preceding groups, multiplication in numbers or reproduction has been effected by the division of the cells or by the formation of more or less modified cells, termed spores. All such methods of repro- duction are called asexual, since but one cell is utilized in the process. In sexu
. Nature and development of plants. Botany. 172 REPRODUCTION OF DIATOMS method of reproduction is termed sexual reproduction. The two fusing cells are looked upon as male and female cells or gametes, although in these simple plants there is no indication of sex that would enable us to recognize them as such. In the preceding groups, multiplication in numbers or reproduction has been effected by the division of the cells or by the formation of more or less modified cells, termed spores. All such methods of repro- duction are called asexual, since but one cell is utilized in the process. In sexual reproduction a cell is formed by the union of the contents of two cells. The nuclei and protoplasmic con- tents of each unite so completely that a cell with but one nucleus and protoplasmic contents results. These sexually produced cells are called gametospores because they are formed by the ^â p^^^. it B Fig. 99. Sexual reproduction of Pinnularia: A two diatoms, enveloped in a mass of jelly. The valves have been thrown off and the content of each diatom has divided into two sexual cells or gametes. B, the fusion of the gametes.âAfter Karsten. union of two gametes and are capable of forming a new plant in the same way as do spores. We may distinguish the spores derived from single cells as asexually formed spores or we may call them simply spores, while the spores formed by the fusion of the two cells or gametes may be termed sexually formed spores or gametospores. Both kinds of spores are devices to enable the plant to increase in number or to meet some other problem. 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 Curtis, Carlton Clarence, 1864-1945. New York, H. Holt
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