Leaf indumentum in some Turkish species of Teucrium (Lamiaceae)

Abstract

Trichome micromorphology can be used as a discriminating character in the separation of species and subspecies. The micromorphologicalcharacteristics of foliar trichomes from five Teucrium taxa (T. scordium subsp. scordium, T. sirnakense, T.chasmophyticum, T. andrusi and T. spinosum) were investigated by scanning electron microscope. Seven types of trichomeswere identified, including glandular and non-glandular. The glandular trichomes were recorded in three types; short clavate,long clavate, and subsessile. The non-glandular trichomes were identified with four types; unicellular thin-walled, 2(5)-celledthin-walled, 3–7(11)-celled flexuose, elongated thin-walled and 2-celled thick-walled trichomes. Generally, the trichometypes were similar on both sides of the leaves, except in T. spinosum. Subsessile glandular trichomes were the most commontype and were occurred in all the investigated species. Also clavate glandular trichomes were found in all the species, exceptT. scordium subsp. scordium. All trichomes were distinctively thick-walled, whereas thin-walled trichomes were observed inonly T. chasmophyticum species. The leaf micromorphology of T. sirnakense and T. chasmophyticum has also been reportedin detail for the first time in this study.