Morphology and distribution of trichomes in Italian species of the Stachys germanica group (Labiatae): a taxonomic evaluation

The micromorphology and distribution of secreting and non-secreting trichomes in different parts of plants of the species belonging to Stachys, S. germanica group, of the Italian Flora, were studied. A peculiar capitate hair with multicellular head was found in all the species examined, with the exception of S. germanica ssp. germanica. This type of trichome is typically 4-celled in S. tymphaea. The distribution of trichomes on the calyces is particularly interesting and some peculiar features better characterize S. germanica ssp. germanica, S. germanica ssp. dasyanthes, S. cretica ssp. salviifolia, S. alpina and S. heraclea.