Research in my lab centers on evolution of morphogenic mechanisms and structure. We use cacti as model organisms because the family contains a great amount of structural/developmental diversity and because the cactus genus Pekeskia retains numerous relictual characters. Plants of Pereskia have hard woody stems and ordinary large leaves. From ancestors like this, morphogenic mechanisms have evolved into ones capable of controlling the differentiation of various types of highly modified wood, unusual types of cortex that have leaf-like features, and apical meristems that minimize the number of mitoses necessary to produce large plants. Because each evolutionary line in the family has undergone particular types of modification of the morphogenic mechanism, we can compare different types of differentiation of a particular tissue, each type controlled by a homologous morphogenic mechanism.