seed germination of myracrodruon urundeuva allem？o (anacardiaceae), a brazilian native tree, was studied under two light conditions (light and dark), both at constant (10, 15, 20, 25, 30, 35 and 40 oc) and alternating (20-25, 20-30 and 20-35 oc) temperature regimes. percentage, speed and distribution of germination were evaluated. seeds germinated either in presence or absence of light, but showed to be preferable negative photoblastic. the germination was null both at 10 and 40 oc, but seeds germinated from 15 to 35 oc. the best germination occurred at constant temperatures from 20 to 30 oc, and alternating temperature of 20-30 oc.