Two modes of reproduction, the vegetative and the sexual: In the vegetable kingdom two modes of propagation commonly occur, known as the asexual or vegetative and sexual respectively. In both cases the new individual arises from a minute piece of protoplasm called a protoplast, but in the first case "this protoplast does not require the special stimulus afforded by union with another protoplast, whereas, in the other, in order that a new individual organism may be produced, a pairing, i.e., a union of the substances of two protoplasts, which have come into being at different spots, must take place."
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