Seed germination of Cecropia pachystachya Trec. was investigated at 25, 30, and 35ºC using fluorescent day lights. Ten replicates each of 200 seeds were used in each thermal treatment. Germitest® paper, CEL-065®, and 11x11x5 cm Gerbox® were also used. The frequencies of radicle protrusions were counted at consecutive two hour intervals. The cumulative frequencies were combined with the distribution of Weibull using the following model: Y = M (1 - exp (-(t/b)c)). The best performance was achieved with the temperature of 30ºC ( M, 95.29%). Time to achieve 60.23% of seed germination (0.6321 x 95.29%) was 99.35 h with a spread of 7.19. All model/data set combinations had close to linear.
Cecropia pachystachya; seed germination; Weibull function
