| Abstract: | Oospores of Nitella furcata subsp. megacarpa (Allen emend. Wood) were collected from an oospore bank in the sediments of Lake George, New York. Incubated at constant temperatures, all or nearly all of the oospores germinated when exposed to a brief pulse of red light when the annual window of germinability was open. The window seems related to the annual cycle of sediment temperatures. It is open in spring and closes wit the onset of a secondary dormacncy in the summer. Oospores in storage follow a parallel path if held at 18°C, a summer equivalent temperature; the window remains open indefinitely if the oospores are held at 4°C. Attention is drawn to the similarity if the cyclic window of germinability in seeds of summer annuals and oospores of N. furcata. |
