Delayed seed dispersal in Pinus torreyana (Torrey pine).

Torrey pine exhibits a pattern of seed release intermediate between an open and closed-cone species. It was found that the cones open at maturity, but that seed fall from some cones continues for up to 13 years. Approximately 77% of the total seed crop was present in age classes one or more years past the time of seed maturity.Serotiny is thought to evolve in response to fire, and partial serotiny at the population level has been attributed to circumstances in which the strong selective pressure of fire is relaxed. We hypothesize that delayed seed dispersal in Torrey pine is a stable trait which is the result of a pattern of large relatively rare crown fires separated by intervals longer than one generation. The reduced serotiny observed in other conifers on headlands and islands in California seems consistent with our hypothesis.