many other carnivores shut down in some seasons. tuberous sundews die back to tubers in the dry season, bladderworts to turions in winter, and non-carnivorous leaves are made by most butterworts and "cephalotus" in the less favourable seasons. "utricularia macrorhiza" varies the number of bladders it produces based on the expected density of prey. part-time carnivory in "triphyophyllum peltatum" may be due to an unusually high need for potassium at a certain point in the life cycle, just before flowering.