Budding in Hydra viridis

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Abstract
The rate of growth of a population of Hydra viridis by budding is shown to be a function of the frequency of bud‐initiations and not of the duration of bud development. Different rates of growth in populations were imposed by feeding the animals three, five, or seven days a week. The slowest growth rate was observed in animals fed Monday, Wednesday, and Friday, while those fed Monday through Wednesday grew at the same rate as hydra fed Monday through Friday. Not only was the duration of the bud development independent of the feeding schedules, but the duration of each of the stages of bud development was also unaltered despite differences in the frequency of feeding. This rigidity is not explained as a consequence of the distal end of the bud prescribing the course and rate of bud development; removal of the distal end, or replacing it with a distal end from a bud or animal at a different developmental and chronological age, had no effect on the development of the original bud's base or the time of its detachment. It seems that bud‐initiation depends on the parental production of a quantum of cells which can completely support the further development of a bud. Differences in the number of buds produced on any parent would thus be a function of the number of quanta produced.