IDENTIFICATION OF EUCALYPTS. 9] 
often of the same color and one edge of the leaf being turned upward and the other 
toward the ground; much less frequently considerably darker above and spreading 
horizontally; oil dots pellucid or concealed; peculiarly and strongly odorous; primary 
veins often numerous and much spreading. Inflorescence either axillary or terminal, 
or more rarely both modes united; flowers in single or paniculated umbels, rarely in 
twos, or solitary; umbel stalks and flower stalklets commonly present, the former 
sometimes much dilated; umbels while very young inclosed in a pair of fugacious and 
sometimes diminutive bracts; calyx very variable in size; lid often provided with a 
minute early deciduous accessory outer layer. 
Calyx of firm texture and separated into a lower persistent portion and a deciduous 
lid. Petals none, unless represented in some few species by an inner membrane. 
Stamens very numerous, inserted close to the edge of the calyx tube in several rows, 
all fertile or some of the outer by absence of anthers sterile, always finally deciduous; 
filaments thread-like, pointed, inflexed while in bud, or the outer or very seldom 
all filaments straight before expansion; anthers dorsified, their two cells parallel or 
divergent, each opening by a marginal or anterior slit or less commonly by a pore. 
Style long; stigma convex or almost flat, undivided, seldom much dilated beyond 
the summit of the style. Ovary 2- to 6-celled, its lower portion grown to the calyx, 
its upper portion more or less free. Ovules in each cell numerous, the majority 
remaining unfertilized. Cotyledons broad, much compressed, somewhat folded, 
undivided or 2-lobed, curved around the cylindrical straight, erect radicle. Fruits 
for a long while persistent, form very small in some species to remarkably large in 
others, oftener smooth than streaked or ridged, valves always glabrous, very rarely 
permanently connected by the persistent base of the style. Seeds long retained in 
the persistent fruit, but soon shed on detachment of the latter; fertile seeds usually 
outside, dark brown; sterile seeds mostly pale brown and smaller than the others. 
DETERMINATION OF SPECIES. 
To identify the species of so large a genus is a difficult task. The 
system of identification adopted below is based on the structure of the 
anthers, the position of the valves, the shape of the lid, the form of 
inflorescence, and the similarity or dissimilarity of the two leaf sur- 
faces. The first thing to ascertain about a Eucalypt that one wishes 
to identify by the use of the key below is the structure of the anthers. 
This can usually be done with a good lens by examining anthers from 
buds just ready to open. In using the key, the second thing to ascer- 
tain is whether the valves of a mature seed case are inclosed within it 
or project partly or wholly from the mouth. It is hoped that the 
accompanying plates will aid in the work of identification. (Pls. XC 
and XCI.) | 
It must be understood that all specimens will not plainly fall into 
any particular subdivision of the genus, and can not therefore be 
readily identified, especially by a beginner. But with a little patience 
and wider experience it will be found that most trees can be identified 
by the use of the keys and reference to the descriptions and illustra- 
tions. When a specimen has been traced to the species to which it is 
thought to belong, it should be ascertained if the species has been 
treated in detail earlier in the publication. If so, reference to the 
description and to the illustrations of the species in question will aid 
