WAITT, DAMON E.*, SARAH HOFFMAN, AND JOCYLEN FOURNET. Department of Biology, Southwestern University, Georgetown, TX 78626. - Meristic variation in wild and cultivated populations of Phlox drummondii.
To determine the extent to which natural populations vary in levels of
developmental instability, meristic variation was assessed in fourteen
wild populations of Phlox drummondii growing in central Texas.
There were significant differences among populations in the
percentages of flowers that exhibited an abnormal number of sepals and
anthers, but not petals or stigmatic lobes. Of the four whorls,
stigmatic lobes varied the most with 4.5% of the flowers exhibiting an
abnormal number. Overall, 8.2% of the 5,022 flowers scored had at
least one anomalous flower. In a separate greenhouse study, five
cultivars and three natural populations of P. drummondii were
grown simultaneously to determine the extent to which the
domestication process has influenced meristic variability. Cultivars
exhibited significantly greater floral formula variation in all four
whorls compared to their wild progenitors. As with the survey of wild
populations, stigmatic lobes varied the most with 17% of the flowers
exhibiting an abnormal number of lobes in the cultivated populations.
Key words: Developmental Instability, Floral Formula, Meristic Variation, Phlox