Physiological integration of physically connected ramets may increase fitness-related traits, such as plant size and reproduction. In contrast, competition among plants may reduce these traits. This study examines the interactive effect of competition and physiological integration on fitness-related traits. Ramet pairs (N=200) from two populations of Viola blanda in southeastern Kentucky were exposed to a competition treatment (with vs. without competitors) and an integration treatment (intact vs. severed ramet connections) in a factorial design. Fitness traits included plant size (total leaf area), sexual reproduction (# of seedpods) and clonal reproduction (# of stolons). I tested the prediction that the presence of physiological integration would reduce the negative effects of competition on plant size and reproduction, whereas the absence of competition would reduce the benefits of physiological integration on size and reproduction, such that fitness values would not differ significantly between the 1) with vs. without competition treatment of ramet pairs with intact connections and 2) intact vs. severed treatment of ramet pairs without competitors. The two populations differed in quality and quantity of light, percent ground cover and soil moisture. The second population of V. blanda produced significantly less total leaf area and number of stolons and had no significant treatment effects. The first population had significant competitive and integrative treatment effects in all three fitness traits. These results suggest that site quality may play an overriding role in plant fitness above that of competition and/or physiological integration.

Key words: Viola blanda , competition, physiological integration