. Plants; a text-book of botany. Botany. THE GREAT GROUPS OF ALG^E 25 about itself. This firm wall indicates that the oospore is not to germinate immediately, but is to pass into a resting condition. Spores which form heavy walls and pass into the resting con- dition are often spoken of as " rest- ing spores," and it is very common for the zygotes and oospores to be resting spores. These resting spores enable the plant to endure through unfavor- able conditions, such as failure of food supply, cold, drought, etc. When favorable conditions return, the protected rest- ing spore is read
. Plants; a text-book of botany. Botany. THE GREAT GROUPS OF ALG^E 25 about itself. This firm wall indicates that the oospore is not to germinate immediately, but is to pass into a resting condition. Spores which form heavy walls and pass into the resting con- dition are often spoken of as " rest- ing spores," and it is very common for the zygotes and oospores to be resting spores. These resting spores enable the plant to endure through unfavor- able conditions, such as failure of food supply, cold, drought, etc. When favorable conditions return, the protected rest- ing spore is ready for germination. When the oospore of Edogo- )iium germinates it does not develop directly into a new filament, but the contents become organized into four zoospores (Fig. 7, F), which escape, and each zoospore develops a filament. In this way each oospore may give rise to four filaments. It is evident that Edogonium is a heterogamous plant, and is another one of the Conferva forms. Conferva bodies are not always simple filaments, as are those of Ulotlirix and Edogonhim, but they are sometimes extensively branch- ing filaments, as in Cladophora, a green alga very common. Fig. p. Cladophora, a branching green alga, a very small part of the plant being shown. The branches arise at the upper ends of cells, and the cells are coenocy tic.— 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 Coulter, John Merle, 1851-1928. New York, D. Appleton and company
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