Development of leaf shape and vein homologies in five species of the genus Ipomoea (Convolvulaceae)

Angiosperm leaves are extremely variable in form while predominantly maintaining the function of the primary photosynthetic organ of the plant. Changes in leaf form can result from myriad physiological processes which may be influenced by ecology, physical stimuli, phylogeny, or other factors. In studying the development of divergent leaf forms among closely related species, conserved morphological elements may be identified that are not apparent in the mature form. The genus Ipomoea (Convolvulaceae) contains over 600 species and a wide range in leaf shapes. Five species, I. purpurea, I. coccinea, I. sloteri, I. quamoclit, and I. cairica show a range in leaf forms from simple to highly dissected. Leaf development was tracked from initiation to maturity in order to identify how developmental trajectories diverge and what is conserved across species. Cleared leaf samples were analyzed and evidence was found supporting the homology between major vein patterns across species. Using these homologous veins, landmarks were established for morphometric analysis. A Generalized Procrustes Analysis was used on landmark coordinates and suggests, through Principal Components Analysis, that the shape described by major venation is conserved across these species despite major divergences in blade form