LEAF MACRO- AND MICRO-MORPHOLOGICAL CHARACTERS AS TAXONOMIC TOOLS FOR SOME ASTERACEAE SPECIES

The morphological and epidermal characters of leaves of 10 Asteraceae species, collected from Dammam city in the eastern region of Saudi Arabia were examined to highlight their significance in identification and classification. Several morphological leaf characters played a crucial role in delimitation of the studied species, including leaf arrangement, type, shape, and the presence or absence of a petiole. Regarding anatomical features, two types of mesophylls were observed, and subsidiary bundles were present in both the petiole and blade. Six types of cuticular ornamentation and 12 different types of trichomes were found. The numerical analysis of the obtained characters demonstrated that the leaf characteristics were taxonomically important for classification and differentiation at the subfamily and generic levels.