Abstract:
In the genus Garcinia, most species are dioecious; moreover, the flowers in this genus are usually very small (5-30 mm) compared to the leaves, making floral-based identification among the species very challenging. Hence, we examined vegetative structures to identify reliable taxonomic characters of 16 species and three varieties covering the entire Western Ghats. Bright-field microscopy revealed several variable features in the leaf, including cuticle thickness, sinuosity of the epidermal cells, number of palisade and spongy cell layers, site of occurrence of druses, resin canals, arrangement of vascular bundles like triangular, arc-shaped, U-shaped or V-shaped with varying degrees of curled distal ends. In petiole anatomy, the outline showed distinct shapes viz. circular, semi-circular or pentagonal, with prominent wings and wavy border. Disparity in petiole anatomy was noted i.e. the thickness of the cuticle, presence of trichomes, vasculature types, druses and resin canals either scattered or in distinct rings. In stem anatomy, variability was observed in the outline like circular, elliptical or squarish with distinct number of wings and wavy margin. Other notable characters viz. hypodermal cells, vascular system, druses, positioning of resin canals in the cortex and pith were found to be noteworthy in identification. The above findings concluded that the distinct anatomical characteristics of leaf, petiole and stem were significant in distinguishing Garcinia species at the vegetative stage.
