The rcproductive biolog-of Ruscus aculeatuc L. was studied at a mediterranean sitc during 1996-1 999. Field obsenations showed that reproductive success was very low, because only 3"h of the marked flowers developed fruits in 1996 and none in 1997 and 1998. Several experiments w-ere performed to investigate the reasons for reproductive failure in this species.Pollen viabilitl-\\-as on average 85%. showing that reproductive failure is not dur to poor pollen quality. Two hand-pollination experiments showed that all flowers are potentially able to develop fruits throughout the flowering period, suggesting that no aberration occurs in sporogenesis, fertilization or post-zygote processes in R. aculeatus and that low reproductive success in the field occurs because of lack of pollination. This hipothesis xras tested b!looking for pollen on the sticgmatic surface of randomly sampled flowers, but without success. Moreover. the bodies of insects trapped in the proximity of the female plants \\'ere carefully checked for pollen but none Lvas found. The number of pollen grains produced per flower is lower than that reported for wind-pollinated species. Nevertheless, tve showed with empirical probes that the possibilih of wind pollination cannot be ruled out. The breeding system and reproductix-e characteristics of R. acu1eatu.r seem to match the traits of the sclerophyllous taxa remnants of the tropical Tertiary flora. hforeover, the climatic fluctuation of the Quaternary and the cstablishment of the mediterranean climate might have changed the conditions of a good pollination process. At present, the low sexual reproduction of R. aculeatus is due to the lack of pollen transport. Within a population of R. aculeatus. genetic variability is re\.ealed by seeds from the few developed fruits which have been shown to be viable. However, maintenance of the individual plants in the population relies on thc resprouting capaciv of the species in question 0 2000 Thr I,imr.in Siicim of-London

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