New species and new record of the genus Teucrium sect. Polium (Lamiaceae) from Iran

Species of Teucrim section polium are widely distributed in the Mediterranean and Irano-Turanian regions. This section contains the most diverse and taxonomically complicated taxa. Iran represents four species of section Polium including T. polium, T. stocksianum, T. capitatum, and the new species described in this paper, T. khuzistanicum sp. nov. During the floristic studies in Khuzistan province, interesting plant materials of the genus Teucrium were collected, expanding our understanding of this genus and resulting in some discoveries. Teucrium khuzestanicum is described as a new species from Iran. The new species is characterized by caespitose habit, long, dense oblong-cylindrical spike-like inflorescence, 1-3 mm long pedicles, and leaf dentations. It is closely related to T. yemenense, but differs from it in indumentum, calyx shape, and flower size and color. Teucrium capitatum, T. polium, and T. stocksianum are the other related species that differ from T. khuzestanicum in their habit, leaf shape, and inflorescence. Furthermore, Teucrium capitatum L. is reported here for the first time in the flora of Iran. In addition, illustrations of the new species, images of the herbarium specimens and living plants in their natural habitat, and an identification key to the species of section polium in Iran are presented, and a geographical distribution map of the new species and its relatives in Iran is provided.