Raciation in Epacris impressa. II. Habitat differences and flowering times

Abstract

The various races of E. impressa occupy different habitats. In east Gippsland, the Otways and the Western District of Victoria, the white-flowered race is found in open sunny sites, whereas the pink-flowered race occurs in more shaded situations. These contrasting habitats-sunny and shaded -frequently form an interlocking distribution mosaic. In these areas the white-flowered race is distinctively spring-flowering whilst the pink-flowered race is winter-flowering. The scarlet-flowered race found at Wilson's Promontory on the granitic mountains has a flowering season from approximately April to November.

The field data presented here strongly suggest that flowering time is a variable which has become modified in regions of sympatry to give a large measure of reproductive isolation between the pink and white-flowered races. In one area of allopatry-the Little Desert-only the white-flowered race occurs where it is winter-flowering.