. The life of inland waters; an elementary text book of fresh-water biology for American students. Freshwater biology. Siphon Algae 121 is known as conjugation, whence the group name) and the development of a protective wall about the result- ing reproductive body. This rests for a time like a seed, and on germinating, produces a new filament by the ordinary process of cell division. These filamentous forms share this reproductive process with the desmids, and despite the differences in external aspect it is a strong bond of affinity between the two groups. The siphon algce—This pectdiar group
. The life of inland waters; an elementary text book of fresh-water biology for American students. Freshwater biology. Siphon Algae 121 is known as conjugation, whence the group name) and the development of a protective wall about the result- ing reproductive body. This rests for a time like a seed, and on germinating, produces a new filament by the ordinary process of cell division. These filamentous forms share this reproductive process with the desmids, and despite the differences in external aspect it is a strong bond of affinity between the two groups. The siphon algce—This pectdiar group of green algse contains a few forms of little economic con- sequence but of great botanical interest. The plant body grows out in long irregularly branch- ing filaments which, though containing many nuclei, lack cross par- titions. The filaments thus resemble long open tubes, whence the name siphon algse. There are two common genera Vau- cheria and Botrydium (fig. 42). Both are mud-lov- ing, and are found partly out of the water about as often as wholly immersed. Vaucheria develops long, crooked, extensively interlaced filaments which occur in dense mats that have suggested the name "green ; These felted masses are found floating in ponds, or lying on wet soil wherever there is light and a con- stantly moist atmosphere (as, for example, in green- houses, where commonly found on the soil in pots). Botrydium is very different and much smaller. It has an oval body with root-like branches growing out from the lower end to penetrate the mud. It grows on the bottom in shoal waters, and remains exposed on the. CT-. Fig. 42. Two siphon algse. A, Botrydium: B, a small fruiting portion of a filament of Vaucheria.; ov, ovary; sp, 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 Needham, Jame
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1915
