Revealing Ha'il's Urban Flora: A Native and Naturalized Plant Species Inventory in Wild and Human-Impacted Habitats, Ha’il Province, Saudi Arabia

The current study documents the vascular wild plants found in ruderal, neglected, roadside, and horticulturally managed (garden) sites in and around Ḥaʾil City, Saudi Arabia. This comprehensive floristic list provides valuable insights and a correlative basis for the exotic plant diversity within the studied area of Ḥaʾil Province in the Kingdom of Saudi Arabia (KSA). This survey resulted in an extensive compilation of 243 vascular plant species belonging to 40 families and 160 genera. The taxonomic structure is dominated by dicotyledonous plants (196 species), along with three families comprising 47 species in the monocotyledons. The spectrum of life forms, calculated according to the system designed by Raunkiaer, is diverse, with a clear predominance of therophytes (141 species), followed by hemicryptophytes (37 species), chamaephytes (35 species), phanerophytes (20 species), one helophyte, and three parasitic plants in the flora, presenting varying percentages of phytogeographic affinities compared to those recorded in the flora as Saharo-Arabian. Notably, 29 species represent newly introduced floristic records for the Ḥaʾil region, of which 8 are new records for Saudi Arabia and are considered new alien plant species. The remaining 214 species include 189 indigenous species, of which 41 are newly introduced native species to Ha’il Province. This will enhance the understanding and knowledge of the exotic flora in Ḥaʾil Province, contributing new information regarding the regional flora and assisting with ecological management to mitigate the impact of the recorded invasive exotics.