68 
The Queensland Naturalist. 
May, 1924 
is ili(.' o-roat variability in most of tlio charavters rolital on 
for cTassificalioo. Tlioro haw sowral si'Ihmuos of 
classification ])ublishecl by different bolariists from time 
to time, each scheme l)eiTij*' based primarily on one par- 
ticular feature, sucJi as barks, anthers, fruits, chemical 
constituents, etc. The various schemes i>roposed by 
different botanists have been ably summarised by Mr. 
J. IL Maiden, in a ]>a])er. ‘'Is Eucalyptus Variable?” 
(Journal and Proceediti^-s of Royal Society, X.S.AY., 
\()\. d(i). and more recently in his “(’ritical IR^vision of 
tile Uenus Eucalyptus.” 
It nec(‘ssarily means, however, that such schemes of 
classification are to a v.ery laru'c extent artificial, trees 
naturally closely allnui bein^' ])laced with' a])art in the 
arran.uaunent of tlie ^'cnus. 
For field work, the bark characters are niuiuestion- 
ahly the most serviceable upon Avhich to oroup the 
s])ecies. The arranoannent of the s])ecies in ^-roups ac- 
cording- to tlieir hark characters was first used by Fer- 
dinand von Mueller, and in his ‘H.h'itieal Revision of the 
(tenus Euealyptus.' ’ J. IF. Maiden has further elaliorated 
Mueller's system. In the arraitu'eaumt wliieh follows, T 
have larjtely followed both iMaiden and Miudh'r, but place 
some of the s])ecies differmitly. T have not allowed the 
group TTemi]>h!oieae, which seems to me an nnuatural one 
that might easily lead to confusion in identifying euea- 
ly])ts in the field. I l]a^'e dividtal this pri'sent pai)er into 
]>arts, llie first being an attimipt to draw iij) a key suit- 
able for fi(dd use. the other ])art or parts to be jmhlished 
in following nnrnhtu’s of the “Naturalist,” Avill be devoted 
to descriptions, with notes on distribution, uses, etc., of 
each species. It must he distinctly understood that the 
key presented herewith refers simjily to the trees as they 
grow in the immediate neighbourhood of Brisbane, and 
is not altogether a})plicable to the same trc'os as growing 
(dsewherc. Even the hark relied on for the main groups 
is a variable feature, particularly in the smooth-harked 
trees or gums proper, where the amount of j)ersistent 
bark varies very considerably; sometimes instead of fall- 
ing off‘ and leaving a smooth, clean barrel, it may be 
more or less persistent. Thus the Scribbly Gum (Euca- 
lyptus micrantha), wliich normally has a smooth, clean 
bole, on tiio Darling Downs (o.g.. Toowoomlia, (Vows 
Nest. etc.), carries a persistent fibrous hark on the- 
ti'unlv and main }>ranclies. 
