Passiflora (the Passionflowers) comprises more than 520 species of vines or small trees with highly specialized flowers that occur in tropical habitats worldwide. Most diverse in the New World, they are represented in the Old World by only about 22 uncommon and poorly known species from Asia and the Austral-Pacific region. Preliminary phylogenetic study indicates that those 22 species descended from a single common ancestor, thus forming a natural group (supersection Disemma). This group differs from other Passionflowers in its floral development, unusual leaf arrangements, and in the diverse array of sugar-producing nectaries found both in the flowers and on leaves and stems, meaning that an understanding of character patterns in this group is essential to understanding patterns of diversity in the genus as a whole. A broad approach will be employed to reconstruct phylogenetic relationships among the species, using characters from morphology and anatomy of flowers and vegetative structures and nuclear and plastid gene sequences. Nectaries will be studied by comparing gene expression among the various forms to address the question of whether they share an underlying genetic basis. A monograph for the section will be completed that will present revised species circumscriptions, illustrations, distribution maps, and keys to facilitate identification of these species, forming an essential basis for conservation efforts for the group.
The project has impact far beyond serving as a dissertation study. The Passionflowers are popular subjects for horticulture and therefore the results of this work can have implications for commercial growers and hobbyists. Extensive collaboration with researchers in Central and Southeast Asia is an integral part of the study. Individuals from botanical gardens and universities in Yunnan, Guangdong, and Hainan provinces of China, as well as Vietnam, Thailand, India, and Papua New Guinea will be involved in the acquisition and study of these species, strengthening ties between US and foreign institutions. Collaboration provides an opportunity for all parties involved to learn about the practical aspects of conserving habitats and the rare species found within them. The monograph, including identification tools for Disemma, will be made available to the public broadly via the World Wide Web. This information will allow identification of rare species of Passionflowers in the wild, facilitating conservation efforts at the level of local management authorities. Live material collected in the field will be cultivated and distributed to botanical gardens in the United States, forming the basis for ex situ conservation efforts. Preserved field collections will be distributed to herbaria, increasing resources for future workers. The developmental study of nectaries will provide a model for how genetic techniques can be used to probe morphological diversity.
