First Report on Taxonomic Significance of Foliar Microanatomy of Lamiaceae Taxa from Pakistan; A Correct Tool for Taxa Authentication

The foliar epidermal, stomatal and trichome properties are frequently used as plant microscopic attributes from a taxonomic or ecological perspective. Among the angiosperm families, the Lamiaceae is one of the most taxonomically difficult, economically significant, and medicinally important families. To better understand the foliar microanatomy of Lamiaceae taxa obtained from Northern Pakistan, this study attempts to determine the variational and diagnostic features of 27 species that were analyzed using light microscopy (LM) and scanning electron microscopy (SEM). UPGMA cluster analysis, principal component analysis (PCA) and semantic differential chart (SDC) were used to characterize, visualize, and compare the leaf micromorphology across all species. Three different types of epidermal cell types were examined on both foliar surfaces i.e., irregular, hexagonal, and polygonal. Anticlinal wall pattern also shows variation. Anomocytic stomata is dominant in 8 studied species followed by paractic in 5 species, anisocytic in 4 species and diacytic in 2 species. The trichomes could be broadly classified into two groups, glandular trichomes (GTs) and non-glandular trichomes (NGTs). Lamiaceae has two types of glandular trichomes, small capitate and large peltate, which differ in size, structure, and distribution. In present research five distinct forms of non-glandular trichomes are unicellular, multicellular, stellate, branched, and unbranched trichomes. The results that characterized, illustrated, and contrasted the leaf anatomical characteristics of the Lamiaceae taxa can be better understood with the aid of statistical analysis. Future research will depend on these findings to improve the systematics of Lamiaceae taxa. These characteristics have a large taxonomic potential when considered as a whole.