Palynological characterization of traditional medicinal plant species from the northern Western Ghats, India

Pollen micro-morphological characters have been widely recognized as valuable taxonomic markers for plant identification and classification. In the present study, palynological features of six medicinally important plant species, namely Mesosphaerum suaveolens, Hygrophila auriculata, Pulicaria wightiana, Barleria prionitis, Exacum pedunculatum, and Canscora diffusa, were investigated using both light microscopy (LM) and scanning electron microscopy (SEM) to assess their taxonomic significance. Field surveys were conducted during the flowering season in November, and nascent flower buds were collected from the north-western Maharashtra. The present research provides detailed information, both qualitative and quantitative, on diverse morpho-palynological characteristics including exine sculpturing, aperture condition, colpi orientation, mesocolpium, spines, polarity, symmetry of pollen grain, pollen shape, polar diameter (P, µm), equatorial diameter (E, µm), P/E ratio, and number of pores. The maximum polar diameter (33.44 µm) and equatorial diameter (32.44 µm) were observed in Barleria prionitis L. (Acanthaceae), while the minimum polar and equatorial diameters were noted in Pulicaria wightiana (DC.), at 9.59 and 10.40 µm, respectively. The pollen grains exhibited diverse aperture types, including Hexazonocolpate, Heterocolpate, Tricolporate, Tricolpate, and Tri-brevicolporate forms. The observed pollen morphology exhibits numerous valuable attributes that enhance the understanding of their taxonomy and play a significant role in accurate species identification. This paper addresses the systematic morpho-palynological documentation of medicinally important plant species that remains scarce in the Indian Subcontinent. The present study addresses this gap by providing detailed pollen morphological data for selected taxa, thereby supporting accurate species identification within their respective families and contributing to an improved understanding of regionally important medicinal flora.