During the Renaissance ecological thinking emerged both in printed scientific works and in pictures showing plants against the background of their natural environment. A unique source for the history of plant ecology is the Libri picturati A. 18–30 collection of water-colours kept at the Jagiellonian Library in Cracow (Poland). This collection consists of 13 volumes of plant pictures, and contains about 1,800 images illustrating more than 1,000 taxa mainly from north-western Europe and the Mediterranean region, but also from Asia and America. Some of these pictures match with woodcuts in various works by famous Flemish botanists, mainly Charles de l'Écluse (Carolus Clusius) (1526–1609). Both the illustrations and their short annotations provide a synthetic review of the ecology of the Renaissance period. The paper deals with ecological issues which are found in the collection such as information on the climatic and edaphic requirements of some species, on plants occurring in various habitats and plant communities, plants representing principal growth forms, descriptions of particular adaptations to specific living conditions, for example the halophyte community of sea coasts or the parasitic flowering plants, and phenological observations. These trends can also be seen in printed publications of that time, and this collection mirrors them especially closely.