Morphological and histological analysis of six Lamiaceae species from the North-Western Indian Himalaya

Abstract

The present work presents a morpho-histological study of six Lamiaceae species, namely Ajuga integrifolia Buch.-Ham., A. parviflora Benth., Pseudocaryopteris bicolor (Roxb. ex Hardw.) P. D. Cantino, Roylea cinerea Baill., Salvia cana Wall. ex Benth. and S. coccinea Buc'hoz ex Etl., native to the North-Western Indian Himalaya region. Histological features have been investigated for the first time in A. parviflora, A. integrifolia, P. bicolor, and S. cana. Salvia cana and S. coccinea are reported to have highly reduced connectives, an unusual trait for the Salvia genus, which typically features elongated connectives forming a lever mechanism. Three types of stomata, anisocytic, anomocytic, and diacytic were observed among the studied species. Pollen grains identified within the taxa exhibit shapes ranging from prolate to sub-oblate and prolate-spheroidal, accompanied by hexa-zonocolpate aperture. Eleven different types of trichomes were identified in the studied species, categorized as non-glandular (5 types) and glandular (6 types). The new insights gleaned from this study contribute significantly to our comprehension and bridge notable lacunae in botanical understanding pertaining to these taxa, heretofore neglected.