Systematic Affinity of Verbena supina (Verbenaceae), a New Species to the Flora of Iran, Along with Infrageneric Classifications of the Genus

Recent evaluation of herbarium specimens in central regions of Fars province led to the introduction of a plant new to the Iranian flora. This novel specimen is introduced as the third distinct species of the genus Verbena named V. supina (Verbenaceae), and a detailed morphological description and illustration of Iranian specimen are provided herein. The genetic affinity of V. supina and allied species were also determined for the first time using nuclear ribosomal DNA genetic marker, and the validity of traditional infrageneric sub-classifications were critically examined. An identification key together with ecological information and the distribution area of this plant within the country, are also discussed. Based on this study, studied Verbena species were grouped into two main clades with distinct geographical dispersion, and the old-world V. supina, is found to be genetically similar to V. officinalis. Morphologically, V. supina and V. officinalis are distinct in terms of seed micro-structure, life form, leaf margin and inflorescence trichome type. The credibility and the monophyly of traditional infrageneric sub-classifications were not validated due to homoplastic characters. Likewise, derived traits such as autapomorphic and synapomorphic were critically determined.