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Few plants have received more attention from investigators in so-called " regeneration" than Bryophyllum calycinum Salisb. The term "regeneration" has been used for the process by which new individuals arise from purely vegetative parts such as from leaf notches in BryophyllU1n. This is the sense in which Loeb (1924) has used the term, making it a "different type" from that occurring in animals in which lost or injured parts are replaced. Much criticism has been directed against the use of this term as applied to plants, since with them the process is one of normal vegetative propagation (Reed, 1923) and not one of replacement of parts. More recently Yarbrough (1932) has offered objection to the use of the term. Although he has clearly pointed out its inapplicability, he has offered no other word as a substitute. It is in lieu of this that we here propose the term " gemmipary " for the phenomenon in question. The word has the advantage of having had current usage, and its application here does not materially broaden its meaning.Members of the Crassulaceae exhibit gemmipary in varying degrees. Bryophyllum, with its numerous meristematic areas distributed along the leaf margin, is capable of producing many individuals from a single leaf, whereas other species with but a single meristematic area develop but one. In this latter class Byrnesia Weinbergii Rose belongs ( fig. I).This species was chosen for study since leaves of it had been observed to produce young plants at their bases very soon after they had fallen off the stem upon the moist soil of a greenhouse bench (fig. 2). The origin and nature of the cells which initiate this new plant and their relationship to the other cells and tissues of the leaf suggested this inquiry. Only the histological aspect was studied and only this aspect is discussed here. Although my results do not parallel those which Naylor (1932) found in Bryophyllum, yet the similarities are so obvious that it is evident we are dealing with the same phenomenon. The greatest difference between our results lies not so much in the nature of the development of the new individual as in the stage of that development at which dormancy of the meristem occurs.In a recent paper Naylor (1932) states that investigations on Bryophyllum have been directed along two distinct lines-viz., the physiological and the histological. The former has received the greater attention. He fully discusses the literature in so far as it deals with the histological phases of Bryophyllum. As the result of his research, he finds that the meristematic 5 62