DO FOLIAGE LEAVES AND BRACTS HAVE USEFULNESS IN THE SEPARATION OF STENOCEPHALUM (VERNONIEAE, ASTERACEAE) SPECIES?

It is well known that the leaf structure has usefulness in the Asteraceae taxonomy. Foliage leaves and bracts (involucral bracts) of six Stenocephalum Sch. Bip. species were investigated with the main purpose of indicating characters for diagnose of species. Leaves e bracts were obtained from herbarium and from the rupestrian fields, and sectioned in rotation microtome. Both leaves were investigated using light microscope and scanning electron microscope. Foliage leaves have epidermis with stomata and glandular and non-glandular trichomes, and are dorsiventral. Bracts also have stomata, indumentum, and parenchymatous and sclerenchymatous mesophyll. The structure of the foliage leaves and bracts has little diagnosis value, but the study allowed to separate some species, mainly those closely related within the genus, as S. hexanthum and S. megapotamicum.