LEAF TYPES IN THE ARACEAE

Leaf types in the Araceae are described and classified on the basis of their morphology and functional role. Four classes are recognized on the basis of their association with the initiation of new shoot axes, the continuation of axes, the resting of axes, or the termination and renewal of axes. The basic types are described with the terms leaf, prophyll, mesophyll, bracteole, mesobracteole, cataphyll, and blastophyll. These terms are modified with the terms monopodial, sympodial, proleptic, sylleptic, resting, flagellar, stolon, reduced, and foliage. This represents an unconventional terminology because some of the modifiers refer to the structure of the stem to which the leaves are attached, rather than to the form of the leaf itself. The intent is to draw attention to the impact of shoot organization on leaf form, and to develop a leaf terminology that will aid in describing shoot organization.