Seed macro-micromorphology and character evolution in Indian species of Jatropha L. (Euphorbiaceae)

Abstract Seed morphology serves as a crucial source of taxonomic and evolutionary information in plants. The ornamentation, sculpturing, and architecture of the seed coat, in particular, hold significant phylogenetic importance. We investigated the seed morphology of 14 Indian Jatropha species using stereomicroscopy and scanning electron microscopy. Macro- and micromorphological characters, such as seed shape, size, color, caruncle morphology, epidermal cell shape, anticlinal boundaries, and periclinal wall ornamentation, were examined. Two seed surface types (reticulate and reticulate-rugose), two primary epidermal cell shapes (polygonal and isodiametrical), three anticlinal boundary types (raised, sunken, and indistinct), and four periclinal wall patterns (flat, concave, convex, and flat to concave) were recognized. Ancestral state reconstruction based on molecular phylogenetic data revealed varying evolutionary trajectories among seed characters, particularly the nature of caruncle and testa showing the strongest phylogenetic signal. These findings demonstrate the taxonomic importance of seed morphological traits and provide insights to understand the character evolution in Indian Jatropha species.