. The Canadian field-naturalist. 1994 Mann: Tolypella (Characeae) in Insular Newfoundland 301. Figure 4. Two typical fertile branchlets exhibiting monopo- dial branching and each with a single antheridium flanked by two archegonia. Abbreviations: 1, lateral branch; m, main branchlet axis. Scale bar = 1 mm. Oospore length averages 390 um (360-415 |um) and width, including ridges, 306 um (290-330 um). The number of ridges (striae) range from 6-8 and average maximum fossae width equals 79 um (63-93 um) in crushed and flattened membranes. Membranes of newly matured oospores are orange- brown where
. The Canadian field-naturalist. 1994 Mann: Tolypella (Characeae) in Insular Newfoundland 301. Figure 4. Two typical fertile branchlets exhibiting monopo- dial branching and each with a single antheridium flanked by two archegonia. Abbreviations: 1, lateral branch; m, main branchlet axis. Scale bar = 1 mm. Oospore length averages 390 um (360-415 |um) and width, including ridges, 306 um (290-330 um). The number of ridges (striae) range from 6-8 and average maximum fossae width equals 79 um (63-93 um) in crushed and flattened membranes. Membranes of newly matured oospores are orange- brown whereas membranes of germinating oospres are darker dull brown in crushed and flattened mate- rial with transmitted light. Oospores which are intact appear dark brown to almost black with reflected light. Membranes are coarsely "granular" with trans- mitted light at 400X, the "granules" being arranged in linear rows as is well described and illustrated in Groves and Bullock-Webster (1920). In older germi- nating oospores the pattern becomes more linearly spongy in appearance. Curiously, Wood (1965) does not mention this coarse linear pattern from the mate- rial he examined, but describes the membrane as "minutely granulate or vermiferous, occasionally smooth" even though it appears to be a key charac- teristic of the species at the level of the light micro- scope. Frame (1977) has shown that the "granular" nature of the membrane as seen with the light micro- scope has been misinterpreted, the scanning electron microscope revealing a spongy or reticulate pattern. Nevertheless, his low power micrographs still reveal a linear pattern to the membrane decoration and this feature will continue to be useful as a rapid check with the light microscope. Taxonomy and Distribution The genus Tolypella is included with the genus Nitella in the tribe Nitelleae characterized by the presence of ten coronula cells and divided branch- lets. Tolypella may be read
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