Raciation in Epacris impressa. I. Corolla colour and corolla length

Abstract

195 populations of Epacris impressa in Victoria, South Australia and Tasmania were surveyed for corolla colour composition. Of these, 75 consisted entirely of plants with white, or pink, or scarlet corollas. These monomorphic populations showed a consistent association between corolla colour, corolla length and anther colour, which suggested that corolla colour is a marker of racial development in this species. Most of the other 120 populations were polymorphic for pink- and white-flowered plants, the content of white-flowered plants ranging from 1 to 99 %. Twenty-six of these polymorphic populations were located in the Grampians and belong to the previously recognized grandiflora race.

Four races are distinguished in E. impressa, marked respectively by short white corollas, long pink corollas, long scarlet corollas, and broad pink or white corollas (grandiflora).

Corolla colour and length in the genus Epacris, and the potential importance of corolla colour and other differences in successful pollination are discussed.