FUNCTIONAL INTERACTIONS AMONG TRAITS THAT DETERMINE REPRODUCTIVE SUCCESS IN A NATIVE ANNUAL PLANT

Fruit production of cocklebur Xanthium strumarium (Compositae) was strongly positively correlated with plant vegetative biomass. Fruit size was negatively correlated with total number of fruits produced. Although larger plants produced more fruit, there was also a significant direct effect on timing of anthesis on total fruit numbers; plants flowering later produced more fruit. The influence of all other traits on reproductive success was indirect through their influence on plant size. Plants with higher water-use efficiencies early in the season produced leaves more quickly; plants which emerged earlier grew more rapidly in height. These faster growing plants had a higher vegetative biomass and consequently a greater reproductive success. -from Authors