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

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.