Morphological variation within Eucalyptus nitens s. lat. and recognition of a new species, E. denticulata

Abstract

The complete geographic range of Eucalyptus nitens s. lat. (shining gum) was sampled to determine the pattern of variation in adult and seedling morphology. Analyses of the different data sets indicated the presence of two distinct taxa: one, characterised by denticulate adult leaf margins, is described as E. denticulata sp. nov.; the other, characterised by entire leaf margins, is E. nitens s. str. Many other characters distinguish the two taxa. Mature trees of E. denticulata have leaves with higher oil gland density, longer peduncles, more cup-shaped rather than barrel-shaped fruit, more frequently exserted valves, and rounded and longer flower buds compared with E. nitens s. str. Seedlings of the two species can be distinguished mainly on the basis that those of E. denticulata have longer internodes and leaves which clasp the stem to a lesser extent.

The major occurrence of E. denticulata is on the Errinundra Plateau, East Gippsland, with limited occurrences in the Baw Baw Ranges and Central Highlands of Victoria. Eucalyptus nitens s. str. is found in isolated stands in New South Wales and Victoria. The two species are allopatric, with the exception of the Baw Baw Ranges and Central Highlands of Victoria where some stands are mixed. Eucalyptus nitens s. str. is also geographically variable, comprising three distinct geographic races: northern and central New South Wales, southern New South Wales, and the Baw Baw Ranges and Central Highlands of Victoria.