MICROMORPHOLOGICAL CHARACTERIZATION OF SELECTED SCROPHULARIACEAE SPECIES FROM PAKISTAN: A COMPARATIVE FOLIAR EPIDERMAL STUDY

Abstract

Foliar epidermal anatomical features provide reliable taxonomic markers that are largely unaffected by short‑term environmental fluctuations. In the present study, twelve species of Scrophulariaceae from Pakistan were examined using light microscopy and a nail‑polish impression technique was used to evaluate the systematic value of epidermal characters. Qualitative observations revealed that all species possess anomocytic stomata; diacytic stomata were not encountered. Trichome presence and density varied markedly: Mazus pumilus and all three Scrophularia species (Scrophularia sp., S. calycina, S. scopolii) completely lacked trichomes, whereas Torenia sp. and Veronica anagallis exhibited the highest trichome densities. Quantitative analysis showed that Penstemon hartwegii had the largest adaxial epidermal cell area, while Veronica anagallis had the smallest. Stomatal density was generally higher on the abaxial surface. ANOVA revealed highly significant differences (P < 0.05) among species for all measured traits, and principal component analysis (PCA) separated the taxa based on epidermal cell dimensions, stomatal area, and trichome characters. The study demonstrates that foliar epidermal micromorphology provides significant diagnostic features for identifying species in Scrophulariaceae, Epidermal features such as stomata type, numbers of stomata and number and types of trichomes, stomatal cell area, epidermis cell thickness, epidermal cell area were measured   from systematic point of view. The collected data then was statistically analyzed through multivariate cluster analysis.