The Application of the Logarithmic Series to the Frequency of Occurrence of Plant Species in Quadrats

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Abstract
Previous work on the frequency distr. of spp. with different nos. of individuals in mixed animal populations has shown that the distr. conforms fairly closely to a "logarithmic series." This present paper is a study of the appln. of the same mathematical approach to the frequency distr. of different spp. of plants in quadrat samples. It is shown that this distr. (whether taken as the no. of spp. found on 1, 2, 3, 4, etc., out of a total no. of quadrats; or as spp. found on 0-20%, 20-40%,.........etc., of the quadrats) is dependent on 3 factors: the no. of quadrats, the size of the quadrat, and a measure of the diversity of the association. This measure of diversity is one of the constants, alpha, in the formula for the logarithmic series, or can be measured proportionately by the rate of increase of spp. as the size or no. of quadrats is increased. The size and no. of quadrats can be varied at will by the observer; the real ecological factor determining the distr. is therefore the diversity of the population.