The incidence of puncturevine (Tribulus terrestris L.) carpels and viable seed recovered from soil samples varied inversely and linearly with depths to 24 cm. Soil type and texture and method of tillage influenced the gradients of carpel distribution and their rate and degree of vertical migration. Evidence for enforced, induced, and innate dormancy in puncturevine seed is presented. Most seed germinated from depths of less than 4 cm in cultivated, sandy loam and clayloam soils. The intra-carpel pattern of seed germination was such that seed located nearest the stylar end of two, three, and four-seeded carpels tended to germinate first, with the other seed tending to follow in order of their position in the carpel from the stylar to the receptaclar end. However, all possible combinations of intra-carpel germination patterns occurred under field conditions.