Abstract. D. Tyteca & B. Tyteca.-Orchids of Portugal Ð 11. A systematic, chorological and cartographic sketch [Natural. belges (Orchid. 1) 67 (1986): 163-192]. The results of six study visits to Portugal are given in the form of systematic and chorological remarks, in the scope of the present knowledge about native orchids in this country. Difficult groups (e.g. Dactylorhiza, Serapias, Epipactis, some species of Ophrys and Orchis) are discussed in greater detail. The numerous data gathered, along with data available from other investigators and from literature, are synthesized in the form of distribution maps. The paper includes the following sections: (1) a brief geographic and climatic outline, (2) the orchids of Portugal: global presentation, list of species and subspecies with systematic and chorological remarks, list of hybrids, (3) cartography: the utm system, list of localities prospected, maps.