XVI International Botanical Congess

The ovule represent only of the most important events enabling the Spermatophyta to predominate on land environment.A proposal is here presented, based on observation of sections of ovules of species of Velloziaceae. In addition to observation of sections of Velloziaceae material, ilustration of teh available literature have shown a universal origin of the integuments from initial pyramidal cells that divide and give rise to new cells, which make up the two layers of each integument. Each of such pyramidal cells corresponds precisely to the pyramidal cell that forward that it corresponds also to the cells that gave rise in fossil materials to the steril telome found around gynosporangium, i.e., the nucellus. (CNPq)