Basal Branching and Vegetative Spread in Two Tropical Rain Forest Lianas

In a primary evergreen rain forest in Veracruz, Mexico, liana recruitment to the forest canopy from the forest floor is commonly by vegetative mechanisms. Two liana species were selected to study this pattern of clonal growth. Ipomoea phillomega maintains extensive stolon systems, colonizing gaps from adjacent undisturbed forest and penetrating undistrubed forest from gaps. Marsdenia laxiflora is restricted to primary forest and its stolon systems generate new liana canopies from deep shade of the forest floor. Both species produce a variety of shoot types, each one with characteristic morphology, growth rate and survival rates of apex and leaves. Vegetative spread is by basal branching (the production of epicromic shoots). It is suggested that vegetative spread by stolons is a natural consequence of hydraulic constraints on liana canopy growth and that this pattern may result in long lives for established liana genetic individuals.