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Species that frequently regenerate sexually after fire were not found in soil seed banks of previous studies in south-eastern Spain (Province of Murcia) and this led to the idea of studying seed longevity in the species concerned. A seed burial field experiment was carried out over a period of 30 months to examine the seed longevity of eight species that mainly reproduce sexually during early postfire succession. In addition, longevity was determined for seeds stored at room temperature and the results were compared to those obtained for buried seeds. Seeds of the study species showed very different patterns of persistence. Water-impermeable seeds of Cistus albidus, Cistus clusii, Fumana laevipes, Convolvulus lanuginosus and Calicotome intermedia survived at least 1 year of burial in high numbers. However, seeds of Calicotome intermedia did not survive a second year, and only approximately 20% of the Fumana laevipes and Convolvulus lanuginosus seeds were alive after 30 months of burial. The longevity of buried water-permeable seeds of Asterolinum linum-stellatum, Teucrium pseudochamaepitys and Stipa tenacissima did not exceed 2 years. When buried for 30 months in a coastal and a mountain population site, the number of viable seeds of Convolvulus lanuginosus and Stipa tenacissima did not differ significantly between the two sites. Seeds of most species showed better survival under room temperature than under burial conditions. We concluded that the seed longevity of some species in soil might have previously been overestimated. [ABSTRACT FROM AUTHOR]