XVI International Botanical Congess

Smilax genus has a wide distribuition and, mostly, Pantropical. Presents, besides aerial climbing stem, which can reach several meters, with vegetative and floral buds, an another bud system, that growth undergroundly. In Smilax quinquenervia, embryo plumule gives rise so an aerial branch that shows, in the begining, an axe with 3-4 nodes in which buds are protected only by cataphyls. The eophyl only arise above this region. Serial sections were made and observed in light microscopy. An underground system analysis permited to observe that is, actually, a stem, with secondary growth, throughtout a lateral meristem. This organ origen is from the cotyledonary bud and all adventitious roots that the plant presents, arise from this organ, wich it was decided to name by rizophore, as because its origen as by its anatomic features. The presence of several stomata on this organ epidermis, possibly, mean that this structure presents aerial clorophyled ancestor.