26 
Eucalyptus populnea F.Muell. and E. brownii 
Maiden & Cambage intergrade extensively 
in central Queensland (Pedley 1969), and 
identification in the overlap zone is achieved 
by applying arbitrary rules such as the length- 
breadth ratio of adult leaves. Eucalyptus 
saligna and E. botryoides intergrade south of 
Sydney (Passioura & Ash 1993) and a number 
of species pairs in the eastern Red gum group 
(Eucalyptus subser. Erythroxyla ) intergrade 
extensively (Brooker & Slee 2000). 
For the Eastern grey box group, numerous 
botanists e.g. Maiden (1921), Blakely (1934), 
Pryor & Johnson (1971), Gillison (1976), 
Hill (1991), Brooker & Slee (1996), Brooker 
& Kleinig (2006), Nicolle (2006) have 
acknowledged that there is intergradation or 
clinal variation between its member species. 
The PhD thesis of Gillison (1976) was an 
attempt to classify the Eastern Grey box 
taxa using numerical taxonomic techniques. 
He proposed a number of subspecies for 
E. moluccana, but these were never validly 
published. 
The range of variation exhibited by this 
group is too great for the recognition of 
only one species, but when four species are 
recognised (as is currently the case), the species 
are very difficult to define and consistently 
identify. Previous reported differences 
between species have often been vague. 
For instance, Brooker et al. (1984) said that 
Eucalyptus moluccana “differs from the other 
Grey boxes E. microcarpa and E. pilligaensis 
in the broader leaves, usually less rough bark 
and taller habit”. Hill (1991) keyed Eucalyptus 
moluccana from E. microcarpa by the bud 
length (not borne out in the descriptions) and 
the width of the adult leaves. 
My field investigations have clearly 
indicated that there is clinal variation within 
and across all taxa, at least in some parts of 
their range. On the other hand, there are clear 
and distinct morphological changes in some 
areas. 
In view of the poorly defined differences 
between taxa and the intergradation between 
them, one could argue that three species 
only (Eucalyptus moluccana, E. albens and 
E. woollsiana ) should be recognised, with the 
Austrobaileya 8(1): 25-34 (2009) 
typical form of E. microcarpa being merged 
with E. moluccana , and the southern New 
South Wales, Victorian and South Australian 
populations of E. microcarpa included with 
either E. woollsiana or E. odorata. However, I 
have maintained the status quo for Eucalyptus 
microcarpa here because of my lack of field 
knowledge of the group in Victoria and South 
Australia. 
As with many other groups within 
Eucalyptus , the identification to species 
of herbarium specimens of Eastern grey 
boxes can be difficult. The juvenile leaves, 
so useful in the classification of Eucalyptus 
spp., are only rarely represented in herbarium 
material. It therefore falls to field observations 
or seedling trials to gather information on the 
juvenile leaf morphology. 
Materials and methods 
The data and descriptions presented here are 
based largely on a morphological study of 
herbarium specimens at BRI and NSW, as well 
as type material at K and MEL. This has been 
supported by extensive field examinations of 
Eastern grey box populations by the author 
throughout much of Queensland and New 
South Wales over the last twenty years. All 
measurements are based on dried herbarium 
specimens. 
Taxonomy 
Eucalyptus series Moluccanae Chippendale, 
FI. Australia 19:501 (1988). Type: E. moluccana 
Roxb. 
Trees, single-trunked. Persistent bark scaly or 
finely tessellated, uniformly grey or mottled 
with various shades of grey; deciduous bark 
grey, white, yellow or coppery, somewhat 
shiny, shedding in long ribbons. Terminal 
paniculate inflorescences and axillary 
simple inflorescences often both present. 
Mature buds with one or more longitudinal 
ridges, sometimes extending to the opercula. 
Opercula two, both shedding at anthesis, 
operculum scar absent. Stamens all fertile; 
filaments white, inflexed; anthers adnate. 
Fruits with deeply enclosed valves. 
