ABSTRACT
Variation in plant reproductive effort (RE) has been related to a variety of factors, including life history strategies, successional stage of habitat , and site-to site variation. Within-species differences in reproductive allocation among sites and between years have also been reported for a number of species and various hypotheses proposed to account for this variability. This chapter discusses the relationship of plant size to absolute and proportional reproductive allocation patterns in two weedy Poa species (P. annua and P. pratensis) and examines whether a size-dependent linear reproduction model is compatible with patterns of reproduction and growth in these species. The study supports the need for consideration of potential size-dependence in studies of RE in plants. The linear relationship between reproductive weight and vegetative weight probably reflects modular growth patterns of Poa species; each tiller is effectively an independent module that produces most of the assimilate required for seed ripening, much of it from the inflorescence itself.
