PRODUCTION AND COST OF FRUITS AND SEEDS I N RELATION TO THE CHARACTERISTICS OF INFLORESCENCE

The levels of seed set and aborted seeds, ovules, and flowers and frui ts were determined in 232 species of planes in relation to inflorescen ce type, inflorescence position, synchronization of anthesis within th e inflorescence and the pollination unit, and the combination of these variables. The percentage of variance between the levels of aborted o vules, aborted flowers and fruits, and seed set was significantly grea ter for inflorescence type than the other variables. The percentage of variance explained by different groups of variables (grouped by clust er analysis) in the abortion levels and seed set does not differ from that of the individual variables. The lowest levels of aborted seeds o ccur in spadices, as well as in axillary and terminal/axillary inflore scences. The lowest levels of aborted ovules and the highest levels of seed set occurred in terminal, capituliform inflorescences. The lowes t levels of flower-fruit abortion were found in solitary flowers and i n terminal, capituliform inflorescences, and in synchronous anthesis. There was a general tendency in this sample for low levels of abortion and high seed sec to be associated with the low cost of fruits and in dividual seeds in inflorescence units. These results are interpreted o n the basis of the biomass assigned to flowers, fruits, and seeds, as well as particular characteristics of the qualitative characters.