THE MATING SYSTEM OF ELATOSTEMA (URTICACEAE) IN RELATION TO MORPHOLOGY - A COMPARATIVE-STUDY

To investigate why some species are dioecious and Others monoecious, a data set of 14 morphological characters in 106 species of Elatostema was regressed onto mating system using partial multiple regression (co ntrolling for subgeneric classification to avoid spurious associations ). Morphology and mating system are significantly related (p = 0.05), and dioecious species tend to have large stipules, woody habit, and la rge leaves. The correlation of dioecy with large stipules is reported for the first time, but this character, like woodiness, is an indicato r of plant size, suggesting a functional relationship of large plants (of the under-canopy) with dioecy.