Glandular trichomes on vegetative and reproductive organs of Lamium orientale (Lamiaceae)

The types of glandular trichomes and their distribution on the vegetative and reproductive organs of Lamium orientale (syn. Wiedemannia orientalis) are studied for systematic purposes in this paper. Two morphologically different types of glandular trichomes (peltate and capitate) are described. Peltate trichomes are characterized by a short stalk, which is connected with a large spherical head composed of four cells in a single layer. Capitate glandular trichomes are subdivided into capitate type A and capitate type B. On the vegetative organs peltate trichomes are abundant, while on reproductive organs capitate trichomes are numerous and the peltate trichomes are rare or absent.