Observations on shoot morphology, anthesis, flower number, and seed production in the Saskatoon, Amelanchier alnifolia (Rosaceae)

This study characterizes some aspects of the reproductive biology of Amelanchier alnifolia, the Saskatoon, including shoot morphology as associated with inflorescence production, timing of anthesis, flower longevity, variability in flower number per inflorescence, and variability in seed number and mass. A typical ramet of the Saskatoon was found to be comprised of long shoots and short shoots, the latter producing flowers and fruits. Anthesis is a mass phenomenon occuring over a two-week period in any given area. The inflorescence is determinate, the most terminal flower always one of the first to bloom. Individual flowers lasted a mean of 3.5 + 1.5 days. Variability in the number of flowers/ inflorescence existed within long shoots, stems, clones, and years. Coefficients of variation for the number of flowers/inflorescence ranged from 6 to 65.5. The number of flowers/inflorescence ranged from | to 15, the mean varying from 5 to 11.3. Single fruit have the potential to produce 10 seeds, but average seed to ovule ratios never exceeded 0.27. Mean seed mass/fruit varied from 1.1 to 6.9 mg. The magnitude of variation of seed mass was 6.27. Mean mass/seed and the number of seeds/ fruit were weakly correlated.