SUMMARY
Our curiosity about the Rutaceae arose due to its confused taxonomy, the number of taxa increased without order with several papers, descriptions of new genera and species in dispersed literature without a monograph of the family since Engler (1896 and 1931). In the State of Amazonas, Brazil, there are 16 genera belonging to the Rutaceae with 29 species (including 2 varieties), whose externai characteristic features are sufficiently distinct to allow the intergeneric and interespecific separation of the studied taxa. The genera that occur in our region are Adiscanthus, Cusparia, Decagonocarpus, Erythrochiton, Esenbeckia, Galipea, Hortia, Leptothyrsa, Monnieria, Myllanthus, Nycticalanthus, Raputia, Ravenia, Spathelia, Ticorea e Zanthoxylum. Ecologically, the family Rutaceae occurs in many kinds of habitats. For example, the species Adiscanthus fusciflorus is found in highland campina and campina forest, and in highland primary and secondary forests. This shows, the adaptability of the species in different ecological habitats. Within the family internal glands are developed which secrete a strongly aromatic oil whose ecological role, according to Haberlandt (1928), probably provides additional protection to the plants against the attack of predators. The woods of the Rutaceae are utilized for several economical purposes and special reference should be given to the species Euxylophora paraensis Huber ("pau amarelo") whose wood is used in the timber industry mainly for parquets, according to Loureiro & Silva (1968). Another species of economical value for the pulp and paper industry is Zanthoxylum rhoifolium Lamarck ("tamanqueira da terra firme") whose wood produces a cellulose yield about 45,1%, as stated by LeCointe (1947). Keys for identification of the genera and species are presented. 40 photographs of the 29 species of the 16 studied genera and 16 figures illustrate this work.