KORN, ROBERT W. Biology Department, Bellarmine University, 2001 Newburg Rd., Louisville, KY 40205. - __The origin of stomatal clusters in Begonia bracteosa.__

The number of stomata in clusters of *Begonia bracteosa* ranges
from one to ten with an average of 3.78 and its distribution follows a
Poisson process as analyzed by the chi square test with a P value
greater than 25%. Each stomatal cluster comes from a single cell with
the number of stomata in a cluster directly related to the size of the
cell at the time of specialization. The probability distribution
frequencies of epidermal cells cam be given as a complex equation that
can be simplified into a binomial distribution which, in turn, can be
restated as a Poison distribution. This set of mathematical
transformations parallels the changes in developmental features from
epidermal cells to stomatal clusters.
**Key words:** begonia, development, stomata