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 occurring 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 plus or minus 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 1 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.