Plants of eastern redbud (Cercis canadensis) from seed collected from native trees throughout the natural range show considerable morphological variation. Characteristics usually associated with xeric conditions, such as increased pubescence, thicker and smaller leaves, and efficient stomatal geometry, are correlated with evapotranspirational trends over the natural range, reaching extremes in western populations. Photoperiodic growth response, time of initiation of dormancy, rate and extent of acclimation, and chilling requirements of dormant buds also vary over the natural range. Plants of southern origin continue to grow under shorter photoperiods than northern plants, and are slower to enter dormancy under short days. Plants of northern origin acclimate more rapidly than southern plants. Degree of acclimation in a fixed time is correlated with climatic parameters as well as latitude and, in the case of first—stage acclimation, longitude as well as latitude. Chilling requirements for breaking bud dormancy increased with latitude, with Florida plants showing no dormancy or chilling requirement.