An investigation of the anatomy, palynology and trichome types of Phlomis olivieri (Lamiaceae)

The anatomy، palynology and trichome types of Phlomis olivieri were studied in order to understand the usefulness of these characteristics for systematic purposes. Results showed that vascular bundles were next to each other in the stem، the mesophyll was composed of 1-layered palisade and 3-4 layered spongy parenchyma. There were two collateral vascular bundles in the centre and two small subsidary bundles in the corners of petiole and there were 4 small vascular bundles in the bracteole. Five main types of trichomes (peltate، capitate glandular، stellate، unicellular simple and dendroid trichomes) were observed. The capitate trichomes were subdivided into three groups: type 1 (short stalk)، type 2 (medium or tri-cellular stalk) and type 3 (long or four-cellular stalk). Stellate trichomes were subdivided into two groups: group 1، sessile or short stalked trichomes and group 2، long stalked trichomes. The dendritic trichomes also were reported for the first time in this species. The pollen grains were tricolpate، relatively large، ovate and the exine ornamentation was reticulate and perforate.