. Fresh-water biology. Freshwater biology. Plant in early stages like Vlothrix, later forming a slender, solid parenchymatous filament; reproduc- tion by zoospores, one from each cell. Quantities of the zoospores are liberated from a filament at a time, the walls becoming partially gelat- inous, but showing a parenchymatous structure after the liberation. By some European writers the genus is regarded as the same as Ulolhrix, but forms such as are found in America must establish it as a separate genus. The zoospores have four cilia and a pigment spot, as in Vlothrix; the vegetative cells may c
. Fresh-water biology. Freshwater biology. Plant in early stages like Vlothrix, later forming a slender, solid parenchymatous filament; reproduc- tion by zoospores, one from each cell. Quantities of the zoospores are liberated from a filament at a time, the walls becoming partially gelat- inous, but showing a parenchymatous structure after the liberation. By some European writers the genus is regarded as the same as Ulolhrix, but forms such as are found in America must establish it as a separate genus. The zoospores have four cilia and a pigment spot, as in Vlothrix; the vegetative cells may change into resting spores. Schhomeris has been found growing on river banks and in quiet fresh water. Fig. 215. Schizomens leibleinii EUtzing. a. portion of filament. X about 625. b. portion of filament showing division in all directions. X 300. c. zoospores. X 635. (Original.) 205 (200) Filament with gelatinous envelop 206 206 (209) Cells not in distinct pairs 207 207 (208) Cells oval, gelatinous envelop homogenous. Hormospora Brebisson. This is regarded by many as being but a phase in the development of Vlothrix. but the very gelatinous membrane, the rounded ends of the cells, and the fact that this form is not known to reproduce by zoospores would indi- FiG. 216. Bornwsporamatabths'BTihismn. Xabout gate that it is an independent genus. 600. (Original.) 208 (207) Cells rounded. Gelatinous sheath showing radial fibrillar struc- ture Radiofilum Schmidle. Chromatophore single, parietal, with one pyrenoid. Cells spherical, ellipsoidal, or lenticular, in some species united by short necks. Filaments unbranched. Reproduction by simple division. Wille includes Hormospora and Radiofilum with Geminella, a genus not known to occur in America. Fig. 217. Radiofilum Jlavescens West. X 300. (After West.) 209 (206) Cells mostly in pairs. 2ro 210 (211) Cells rounded, gelatinous substance lamellate, invested by the antecedent mother-membrane. . Binuclearia Wittrock. Filaments attached when yo
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
