On A.J. Underwood's model for a random pattern.

Three different "random" spatial models, incorrectly treated as identical by Underwood (1978), are described and their distinctness noted.

Salt marsh vegetation: Latitudinal gradients in the zonation patterns.

Zonation patterns of salt marsh vegetation were examined at latitudes ranging from 44°40'N at Halifax, Nova Scotia, to 58°50'N at Churchill, Manitoba. It was found that in all areas examined the landward boundaries of the species' zones were more nearly coincident (i.e.