{\rtf0\mac \deff0 {\fonttbl {\f0\froman Times;} {\f1\froman Geneva;}{\f2\fmodern Courier;}{\f3\froman Geneva;}{\f4\froman Times;}{\f5\froman Geneva;} {\f6\froman Times;}{\f7\fmodern MS LineDraw;}{\f8\fdecor Symbol;}} {\colortbl;\red0\green0\blue0;\red0\green0\blue127;\red0\green127\blue0;\red0\green127\blue127;\red127\green0\blue0;\red127\green0\blue127;\red127\green127\blue0;\red127\green127\blue127;\red63\green63\blue63;\red0\green0\blue255;\red0\green255\blue0;\red0\green255\blue255;\red255\green0\blue0;\red255\green0\blue255;\red255\green255\blue0;\red255\green255\blue255;}\linex0 \sbknone \margl1440 \margr1440 \margt1440 \margb1440 \plain \headery1440 {\stylesheet {\snext0 Normal;} {\s2 \sl240 \qj \tx720 \sbasedon0 \snext2 p0;} {\s3 \sl200 \qj \tx720 \sbasedon0 \snext3 p1;} {\s4 \sl200 \qj \tx740 \sbasedon0 \snext4 p2;} }\fs18 \f0 \fs12 \f0 \b \linex0 \linemod0 \sbknone \headery1440 \pard \s3 \qj \sl-200 \tx720 Abstract.- \fs16 \f0 \plain \fs16 By analyzing 296 published and unpublished data sets describing annual variation in seed output by 144 species of woody plants, this article addresses the following questions. Do plant spe\-cies naturally fall into distinct groups corresponding to masting and nonmasting habits? Do plant populations generally exhibit significant bimodality in annual seed output? Are there significant relationships between annual variability in seed production and pollination and seed dispersal modes, as predicted from economy of scale considerations? We failed to identify distinct groups of species with contrasting levels of annual variability in seed output but did find evidence that most polycarpic woody plants seem to adhere to alternating supra-annual schedules consisting of either high or low reproduction years. Seed production was weakly more variable among wind-pollinated taxa than animal-pollinated ones. Plants dispersed by mutualistic frugivores were less variable than those dispersed by either inanimate means or animals that pre\-dominantly behave as seed predators. We conclude that there are no objective reasons to perpetuate the concept of mast fruiting in the ecological literature as a shorthand to designate a distinct bio\-logical phenomenon. Associations between supra-annual variabil\-ity in seed output and pollination and seed dispersal methods sug\-gest the existence of important reproductive correlates that demand further investigation.\par \pard \qj \sl-200 \tx720 \par \i \pard \s4 \qj \sl-200 \tx740 Keywords:\tab \plain \fs16 crop size, mast fruiting, pollination, seed dispersal, seed production.\par \fs18 \f0 }