Neophytes and archaeophytes
Plants that have been introduced into an area, are separated into archaeophytes and neophytes, the former having come before the establishment of the trans-Atlantic contacts around the year 1500, the latter after that date.
Archaeophytes are usually considered an enrichment of the flora. About neophytes there are often very emotional arguments whether some of them, the so-called "aggressive" or "invasive neophytes", are a threat to the indigenous flora. Most neophytes however do not play an invasive role and cannot compete against native plants.
French: néophytes / archéophytes