. A manual of botany. Botany. THALLOPHYTA—ALG^ 57 Siphoned.—These are the most remarkable forms of the group, the thallus consisting of a single coenocyte, often of very large dimensions, or of a number of ccenocytes attached to each other, forming a filament. The largest members of this family belong to the genus Caulerpa, which in many cases simulates the different types of habit exhibited by terrestrial plants. The stem and leaves are nearly always well represented, and the root system is clearly differentiated. The internal cavity of the coenocyte is crossed by interlacing strands or trabe
. A manual of botany. Botany. THALLOPHYTA—ALG^ 57 Siphoned.—These are the most remarkable forms of the group, the thallus consisting of a single coenocyte, often of very large dimensions, or of a number of ccenocytes attached to each other, forming a filament. The largest members of this family belong to the genus Caulerpa, which in many cases simulates the different types of habit exhibited by terrestrial plants. The stem and leaves are nearly always well represented, and the root system is clearly differentiated. The internal cavity of the coenocyte is crossed by interlacing strands or trabeculse formed of a modification of cellulose, and springing froni the outer wall of the structure. A form of much humbler type, but more familiar to us from its occurrence in fresh-water and in muddy Fie. Fig. 805. A. s^. Newly formed zoospore or zoogouidium of Vaucheria sessilia escaping. B. Zoospore at rest after having lost its cilia, c. First stage of germination. D. Filament of Vaucheria sessilis producing oogouia, 0(j, off, and antheridium, h. w. Hyaline root-like process, forming a sort of mycelium, sq. Zoospore, which by germinating lias formed the filament. After Sachs. places, is Vaucheria (fig. 805), The plants are filamentous ccenocytes, which branch irregularly or dichotomously. There is but little differentiation, but from some of the filaments curious root-like structures are developed for purposes of attachment. Other forms are Aceiabidaria, where there are stalks crowned by whorls of coherent leaves, and Botrydmm {fig. 804), where a bladder-like head is continued downwards by a slender stalk to a much-branched root, aU being a single ccenocyte. Forms composed of several ccenocytes united into a filamentous thallus are shown by the genera Sphceroplea, Cladophora, &c. The curious genus Hydrodiotyon is sometimes referred to this Please note that these images are extracted from scanned page images that may have been digitally enhanced for reada
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