ON E. C. PIELOU'S INDEX OF NON-RANDOMNESS.

The article presents E. C. Pielou's devised valuable index of non-randomness of the distribution of a plant population which intends to test for a departure of a plant distribution from randomness and serves as a measure of the amount of non-randomness in the distribution in the case of a non-random distribution. Pielou has only cited the sampling errors of the point-to-plant distances. It is noted that the devised index is computed from the information supplied by a sample of point-to-nearest-plant distances as well as the second sample of quadrat counts.