ANOTHER APPROACH TO LEAF SHAPE COMPARISONS

Abstract

Summary Methods for shape comparisons among groups originally developed in zoological studies are found to be useful in examining variation in leaf shape. These methods (sampling outlines by means of truss networks connecting landmarks or pseudolandmarks, and sheared principal components analysis) take advantage of electronic methods of data capture and multivariate data analysis. They have the desirable properties of discriminating between shape variation and variation in size, and of permitting their results to be related directly to the original measurements from which they were obtained. The utility of these methods is demonstrated with respect to a search for possible leaf shape intermediacy in putative Crataegus hybrids, and an examination of geographic variation in the cross‐sectional shape of Larix laricina needles.