Mericarp morphology and its systematic implications for the genus Salvia L. section Hymenosphace Benth. (Lamiaceae) in Turkey

Abstract

Mericarp morphology of 15 taxa of Salvia L. section Hymenosphace Benth. in Turkey were investigated by light microscopy (LM) and scanning electron microscopy (SEM) to evaluate the utility of mericarp characters in systematic studies. Mericarps ranged from 2.50 to 5.38 mm in length and 2.04 to 4.70 mm in width. Mericarp shape was prolate-spheroid or near spherical with a length-to-width ratio of 1.02–1.48. Transverse sections of the mericarps were rounded or rounded-trigonous. Mericarp surfaces presented colliculate, reticulate, verrucate or foveate sculpturing patterns, mostly as a result of the sculpturing of the exocarp cell walls with the pattern determined by whether the periclinal walls were concave or convex and whether the anticlinal walls were raised or sunken. Colliculate surface sculpturing (periclinal walls convex) was the most common among the taxa examined. The variation in the nature of surface sculpturing, mericarp shape and size, exocarp cell shape, nature of transverse sections and abscission scar diameter proved useful diagnostic characters. Variation was sufficient to distinguish taxa at species level, including morphologically similar species. Data provided here are also relevant to phylogenetic questions at higher levels within Salvia.