Testing Systematic and Evolutionary Hypotheses in a Primitive Neotropical Group of Violets (Viola sect. Leptidium)

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The "true" violets, belonging to the genus Viola, comprise a large and verydiverse group of plants that is found worldwide but is especially rich inthe mountain regions of the Latin American tropics. Like many othertropical plant groups, Latin American representatives have received littleserious scientific attention. Studies are desperately needed to understandspecies diversity there, clarify distinctions of species and figure outrelationships among them, and eventually to illuminate evolutionaryprocesses of diversification. Recent molecular studies of Latin Americanand other violet groups worldwide by the Principal Investigator demonstratethat Latin American violets are the oldest and most primitive of all.Thus, investigations on these violets will reveal important clues regardingthe origins of violets around the world, their evolution, global migrationand remarkable success. One of the two largest violet groups in LatinAmerica, section Leptidium, is the focus of the funded research.Field expeditions to Colombia and Venezuela, Peru and Bolivia, andsoutheastern Brazil, will be made to study populations of all species ofsect. Leptidium in the field and to bring back flowering and fruitingmaterials for intensive laboratory studies. Details of flowers, leaves,capsules and seeds will be compared among field-sampled populations, andagainst thousands of museum collections on loan from other botanicalinstitutions, to determine recognizable species. A compositerepresentative from each of several populations of each species will bebrought back from the field expeditions for molecular investigations. Twotypes of molecular data, DNA sequences from the nuclear InternalTranscribed Spacer region, and highly variable Inter-Simple Sequence Repeatmarkers, will be generated from the population samples to interpretrelationships between populations and species in section Leptidium.Chromosome numbers taken from flowers of species in the group, and physicalcharacteristics of species, will be compared with other groups of violetsaround the world, in order to interpret evolutionary patterns in the "true"violets as a whole. A traditional taxonomic treatment will be completedfor species in section Leptidium, to serve botanists and naturalists whoencounter these violets in Latin America.