The exotic flora of Chad: a first contribution

A first inventory of the exotic flora of Chad has been compiled on the basis of the published literature, original distribution data collected by Global Positioning System field surveys (1999 to 2003), and plant exsiccata. A strictly geographical and conservative approach was adopted including only cultivated species and those with a native range separated from Chad territory. The reported aliens (131 taxa) represent approximately 6% of the total flora of the region (ca. 2,250 taxa). Most were introduced deliberately after 1823 (neophytes), from Central and tropical America. Agricultural weeds and ruderal species accounts for the 18%. Because source data may be underestimated, further assessments are proposed.