Alán Fonseca , Elizabeth- Tropical wild plants.- Cartago: Editorial Tecnológica de Costa Rica,2001. 212p.:il ISBN 9977-66-126-X This publication presents thirty species of plants, which can grow wildly, that is they have not been sown on purpose, in altered environments. Under certain circumstances, these species can cause problems to the agricultural, livestock and forest production. They can also bring benefits and be useful to humanity in numerous ways. For these reasons, it is better to call them "Will plants", instead of using names, such as "weed", that express only the negative aspect. It is expected that this compilation contributes not only to determine the management plans to reduce the interference of the wild plants in crops, but also in the assessment and the exploitation of their practical use and agroecological importance.