WITHIN AND AMONG FLOWER SEX-PHASE DISTRIBUTION IN ALSTROEMERIA-AUREA (ALSTROEMERIACEAE)

Although dichogamy is a prevailing feature of the angiosperms, the sim ultaneous change from male to female phases among hermaphrodite flower s within a plant (i.e., synchronous protandry) has been reported for o nly a few families (e.g., Araliaceae, Umbelliferae). Here we present a n example of synchronous protandry at the ramet level in the Alstroeme riaceae. Dichogamy was analyzed in clonal Alstroemeria aurea at the fl ower, ramet, and at the whole flowering patch level. Alstroemeria aure a is self-compatible but totally dependent on biotic agents for pollen transfer. There was evidence of strong inbreeding depression expresse d during seed development. Comparisons of seed set in open-pollinated flowers with those obtained after hand selfing and outcrossing resulte d in a selfing rate of 0.3. At the flower level protandry was complete . The male phase lasted about 4 days and the female phase lasted about 3 days. Between the female and male phase, there was an approximately 1-day long ''neuter'' phase. Flowering ramets produce a terminal infl orescence bearing one or more whorls of flowers. Within a ramet, flowe rs of the same order opened within a period of 1-2 days, and male and female phases of different flowers did not overlap. When inflorescence s held two whorls of flowers, the ramet went through two alternating n on-overlapping male-female cycles. Using spatial autocorrelation techn iques, we found little evidence for pairs of neighboring ramets expres sing the same sexual phase beyond random expectations at any scale ran ging between 0.25 to 15 m. By ensuring pollen interchange between flow ering ramets, synchronized protandry at the ramet level could be an im portant feature in reducing selfing in A. aurea.