Fog oases during the El Nino Southern Oscillation 1997-1998, in the coastal hills south of Iquique, Tarapaca region, Chile

The flora of four fog oases in the northern Chilean coastal desert, visited between October 1997 and January 1998, is described. These botanical colle ctions are new for Alto Patache, Punta Lobos and Alto Chipana. A total of 7 2 vascular plant species were registered, contributing to the area's floris tic knowledge, where till now only about 20 species were registered. Three species are new records for the chi lean flora: Nolana adansonii (Room. et Schult,) Johnst., Solanum cfr, montanum L. and Ophryosporus cfr.floribundus (D.C.) King et Rob., and another one Alstroemeria lutea (Mu (n) over tilde oz 2000) is a new species. This last one, together with Eulychnia aricensi s Ritter, Pyrrhocactus saxifragus Ritter (both Cactaceae) and Nolana intons a Johnst. (Nolanaceae) are local endemics. Of the total of registered speci es, 43 % are endemics. 52.7 % are non endemic natives and a low percentage (4.1 %) are foreign species' 47.2 % share their distribution with Peru. The families Asteraceae, Nolanaceae and Solanaceae, are the best represented i n the area, each one with more than seven species. Information about specia l climatic conditions due to El Ni (n) over tildeo 1997-1998 event is discu ssed in relationship to the development of the flora and vegetation. In spi te of a non significant occurrence of rainfall events, an increase in tempe rature and in the fog's water content is detected. These conditions favor t he development of more exuberant vegetation and the expansion of the distri bution range of some floristic elements.