Anatomical, Ecological and Trichome Micro-Morphological Features of Two Marrubium L. Taxa (Lamiaceae)

Abstract

The anatomical, ecological and trichome micro-morphological features of two taxa (Marrubium amasiensis and Marrubium parviflorum subsp. parviflorum) belonging to the genus Marrubium were determined and these features were compared. M. amasiensis is endemic and is distributed only around Amasya in Türkiye. In anatomical examinations, cross sections were taken from the root, stem, petiole, leaves and surface sections were taken from stem, petiole, and the lower and upper surfaces of the leaves. When the anatomical findings were examined, multi-layered lamellar collenchyma layer was encountered at the corners of the stem. The studied taxa have equifacial leaves in terms of mesophyll structure. Stomata of M. amasiensis are anomocytic and rarely anisocytic type, while stomata of M. parviflorum subsp. parviflorum are anomocytic type. The margins of the adjacent cells of the stomata in both taxa are very undulate. Eglandular and glandular trichomes were seen on vegetative organs of the two taxa. The eglandular trichomes are stellate, dendroid, marrubioid and simple unicellular types, while glandular trichomes are capitate and peltate types. Dense stellate trichomes were found in the vegetative organs of the studied taxa. Since the head and stalk cell numbers of capitate trichomes showed variation, these trichomes were divided into subtypes. Three subtypes of capitate trichomes were found on the vegetative organs of M. parviflorum subsp. parviflorum, while four subtypes of capitate trichomes were found on the vegetative organs of M. amasiensis. Soil samples were taken during flowering periods of taxa, physical and chemical properties were determined. Some similarities and differences were detected in the anatomical, ecological and trichome micro-morphological features of the studied two taxa. It has been emphasized that these different features will be used as valuable taxonomic characters in distinguishing of the two taxa.