Tachigalia versicolor is a monocarpic canopy tree species on Barro Colorado Island, Panama. This 2-yr demographic and physiological study examined whether seed and seedling survival of thes monocarpics species is higy compared to nonmonocarpic species previously studied, as life history theory predicts. For the weighted average of two trees, the percentage of offspring estimated to survive from dispersed seed to germination, 1 yr, and 2 yr was 30,7.2,4.3, respectively. The large seeds (500-600 mg) suffered greater mortality in absolute numbers than did the seedlings. Major mortality agents of seeds were bivores and damping-off fungi killed seedlings. Seedling survival and growth were enhanced and nonconspecific adults. The majority of 2-yr-old seedlings occured within 0-40 m fron the parent trees, reflecting the original peak of the distribution of wind-dispersed seeds. Few seedlings persisted beyond 40 m. Seedling survival in the first 2 mo was higher in shade understory than in ligh-gaps than shaded understory. T. versicolor seedlings exhibited a wide range in maximum net photosynthetic rate when grown in contrasting light conditions, and were able to acclimate to a sudden increasein light level by means of morphological and physiological adjustments of newly developed leaves. these results indiate that T.versicolor can utilize a wide range of light environments in the forest during eedling establishment.