Catalogue of the naturalized flora of Taiwan.
A study was conducted from 2000 to 2003 to compile a comprehensive list of naturalized species with background information, including origin, life form, habit, usage, year of the first collection and status. Major herbaria (TAI, HAST, TAIF and NCKU) were visited to examine specimen records. Relevant publications and reliable websites and many other resources were also examined extensively for background information. A total of 341 species in 222 genera and 60 families were documented as naturalized in Taiwan, representing 7.9% of the local flora. Besides, 25 species were considered as possibly naturalized due to insufficient evidences. A large portion (90.6%) of species reported here, were reported as "weeds" in other countries. Almost one-half of the naturalized species (48.3%) were introduced from Americas.