"La fecha de introducción de las plantas invasoras en nuevas regiones es de gran relevancia ecológica, evolutiva y biogeográfica, pero suele ser difícil de determinar. Las fuentes históricas de la época de colonización europea pueden contener datos relevantes sobre la llegada de taxones no nativos a América. Durante el Periodo Misional Jesuita (1697- 1768) se establecen los primeros asentamientos humanos permanentes y se introduce la agricultura y la ganadería en la Península de Baja California (PBC). Se revisaron textos escritos por los misioneros de esta orden relativos a la PBC y se encontraron datos precisos en la crónica de Miguel del Barco sobre la presencia y abundancia, en la primera mitad del siglo XVIII, de dos plantas actualmente invasoras en la región: Arundo donax y Ricinus communis.""The date of introduction of invasive species in new areas is of high ecological, evolutionary and biogeographical relevance, although it can be difficult to determine. Historical sources on the European colonization period may contain relevant data about the arrival of some non-native taxa in America. During the Jesuit missionary period (1697-1768) in the Peninsula of Baja California (PBC), the first permanent human settlements were established and agriculture and livestock were introduced. Written sources by Jesuit missionaries who were present in the PBC were reviewed and precise data were found in the chronicle of Miguel del Barco regarding the presence and abundance of two currently invasive plants Arundo donax and Ricinus communis, which were already present in the PBC by the first half of eighteenth century."