Abstract
This investigation revealed that there are 42 species belonging to fifteen families in eleven governorates of KSA. The highest number (seven) and percentage (20.60%) of introduced species were recorded in Dammam and Riyadh, while, the lowest values were recorded in the regions of Al-Baha, Al-Ghat and Jizan (one and 2.94%). As for Al-Baha a large number of introduced species (nineteen, 46.34%) were recorded, nearly half of the number of species examined, while no invasive species were recorded in Bisha, Dammam, and Tabuk. The life growth of the introduced species ranges from trees to young weeds. Phanerophytes (45%) had the highest proportion of life expectancy for the introduced plants, followed by Therophyte (40%) and Chamaephytes (15%), while the highest percentage (63%) among life ratios of the introduced and invasive plants was recorded for Therophyte, and the percentage of life growth of introduced plants indicates the dominance of herbs among other life forms. Regarding the total growth of life, the highest recorded percentage was in herbs (50%), followed by shrubs (19.05%), trees (16.67%), bush (9.52%) and grass (4.76%). The biological growth of weeds was dominant for the invasive plant species, followed by trees in the introduced species, and shrubs and trees in the introduced and invasive species. These indicate that the annual species and invasive weeds are better adapted to the environmental conditions in the studied areas in KSA.