The pattern of variation in leaflet shape and reproductive characters in Lathyrus vernus (L.) Bernh. (Fabaceae)

Abstract.

The pattern of variation in characters closely connected with reproductive fitness and in a presumably weakly selected character, leaflet shape, was studied in the forest-herb Lathyrus vernus. Plants from twenty populations, representing three geographically distinct regions (C. Europe, S. Sweden and C. Sweden), were transplanted to a common garden. Leaflet shape, described using elliptic Fourier coefficients and moment invariants, showed significant variation between regions and between population within regions, and a tendency for differences in leaflet shape to increase with the geographic distance separating the populations. Pairwise comparisons of populations also revealed a positive association between the difference in leaflet shape (when quantified using moment invariants) and the genetic distance based on allozyme data from an earlier study. There were significant between-population and between-region differences for most of the reproductive characters, whereas the association between the between-population distance in reproductive characters and geographic or genetic distance failed to reach significance. Leaflet shape and reproductive characters generally showed higher levels of differentiation than the allozymes. L. vernus did not show any significant differences in fitness-related characters between small and large populations measured in cultivation, although individuals from small populations flowered earlier and had a higher mortality during four years in cultivation.