Nutlet morphology and pericarp structure of 16 species in the genus Lycopus were studied by light microscopy (LM) and scanning electron microscopy (SEM), and a detailed description of nutlet morphological features for all examined taxa is provided. The nutlets of all taxa in the genus Lycopus are well adapted to typical hydrochory (or nautochory) with an air-filled pericarp, and myxocarpy was not at all found. It is noteworthy that the nutlet morphology (in particular the shape of corky crests and corky ring and the distribution of glandular trichomes) and pericarp anatomy of Lycopus are unique and are well distinguished from the other genera in the tribe Mentheae. We also found some groups of the species within the genus Lycopus by the present nutlet morphological and anatomical data that appear to be useful as diagnostic characteristics for delineation purposes at the specific/interspecific levels. The earlier infrageneric classification for the genus Lycopus is, however, not well supported by the present results. In addition, the systematic and biological implications of the nutlet characteristics investigated are briefly discussed.

A comparative micromorphological study of leaves was carried out on 102 species of Mentheae; 61 species were selected for the anatomical study. Mentheae possessed both amphistomatic and hypostomatic leaves. The diversity of leaf epidermal characteristics was based on the variation in morphology of epidermal cells, stomata types and trichome types. Although each characteristic on its own has rather limited systematic value, the combination of some of these features may be systematically relevant, especially for the identification of species. For example, branched multicellular nonglandular trichomes were a diagnostic characteristic for all genera investigated of the subtribe Salviinae; however, this trichome type was also observed in Hedeoma ciliolata and Neoeplingia leucophylloides of the subtribe Menthinae. Capitate glandular trichomes with pear-shaped heads were only observed in Salvia dorrii. Subsessile glandular trichomes with multicellular heads (more than ten cells) were an apomorphy for Perovskia. The anatomical leaf structure was consistent throughout the tribe. In some species, the vascular bundles in the midrib were modified into a mechanical tissue, which is an adaptation to xerophytic environments. The observed variations are discussed in an ecological context and their phylogenetic significance is evaluated.

The pollen morphology and ultrastructure of the subtribe Salviinae were investigated with light, scanning electron, and transmission electron microscopy. In addition, cladistic analyses of the obtained morphological data, supplemented with rbcL data from GenBank, were conducted in order to assess the phylogenetic signal of palynological characters. Salviinae pollen is small to large, oblate to prolate in shape, with a circular to slightly elliptic amb, and mostly hexacolpate. Perovskia abrotanoides appears to be distylous and shows a significant pollen dimorphism between pin and thrum flowers. The sexine ornamentation of the genera Lepechinia and Chaunostoma is perforate, while the ornamentation of other genera is bireticulate. Perovskia expresses a unique type of sexine ornamentation. The sexine ornamentation variation in Salvia has systematic importance but only partly corresponds with current phylogenetic hypotheses. Unbranched columellae and a continuous, granular endexine are hypothesized to be a symplesiomorphic condition in the tribe Mentheae. Our combined phylogenetic analyses show that the addition of palynological characters contributes to improved resolution and also increases bootstrap support values in comparison with molecular phylogenetic analyses.