In the context of an automated leaf identification process, the use of thorough leaf margin descriptors is essential given the importance of this criterion in the determination of the species. The spatial properties of teeth along the leaf contour are something to keep track of, which is made possible through the use of structured representations. This paper introduces a sequence representation of leaf margins where teeth are viewed as symbols of a multivariate real valued alphabet. It presents the methods developed to make use of this description for classification and implementation in a mobile tree identifying application. The results of various classification methods are compared and discussed, both in terms of species recognition and of consistency with botanical concepts.