European scientists initiated lichenology in Puerto Rico in the 19th century. Activity of the discipline increased notably on the island during the first three decades of the 20th century, primarily by the field explorations and publications of the New York Botanical Garden scientists and associates (A. A. Heller, N. L. and E. G. Britton, L. W. Riddle), and by the work of Bruce Fink of Miami University in Ohio and collaborators (E. A. Vainio, A. Zahlbruckner). Another period of research activity began in the late 1950s and was initiated by Henry Imshaug of Michigan State University. By the last decades of the century, the first contributions of Puerto Rican lichenologists I. Landrón-Concepción and J. Mufiiz-Acevedo were made. Because of these efforts. Puerto Rico is among the best documented islands of the Caribbean in terms of its lichen biota. In spite of contributions spanning over a century, the development of knowledge and local expertise is today slow-paced. Training students and the development of new taxonomic and collecting activities are fundamental to addressing shortcomings of the discipline and in laying the foundation for future work in the field. To allow further development of lichen studies in Puerto Rico, we have constructed an electronic checklist of all previously reported taxa (available at  http://lichensofpuertorico.herbario.upr.edu), and a current bibliography on Lichenology for the island.