7 
BARK. FIRST LEAVES. 
obvious to the eye, and as non-fibrous when no distinct fibres can be easily detected 
in them. The group includes the several forms known as “box barks” and also the 
“woollybutt barks.” 
4. Hard barks with longitudinal and sometimes transverse ridges and furrows. 
Of this group the most important are the ten or eleven species technically called 
“ironbarks”; but besides the true “ironbarks” there are several other species that 
carry on their stems and more or less on their main branches a coating of very 
firm and deeply furrowed dead bark. The “blackbutt barks” of Western Australia 
fall into this group, and are thus in contrast to the soft “blackbutt barks” of 
Eastern Australia included in group (1). 
5. Hard, non-fibrous barks that sometimes appear as irregularly cracked and 
fissured plates at the base of otherwise smooth barked trees. These plates are 
often loosely attached and may at any time fall away. 
In ordinary field work what one first and most observes is the surface of the 
tree, the presence or absence of dead bark upon the stem or stem and branches, and 
the character of such dead bark if present. A competent investigation into the 
texture of the living part of Eucalyptus barks could not fail to reveal distinctions 
that would be helpful in specific determination; but the task would be slow and 
difficult and would require laboratory work. 
(c) FOLIAGE. 
When studying foliage in the bush we usually give our attention first to the 
mature or adult trees and afterwards look round for their young offspring. In 
writing on the subject it will be equally convenient and more scientific to reverse 
the order and follow the life of the tree from the germination of the seed to 
maturity. 
SEED LEAVES OR COTYLEDONS. 
The genus Eucalyptus belongs to that great division of plants in which each 
seed contains two nutrition lobes. It is one of the genera in which these two lobes 
develop at germination into organs like leaves. Seed leaves or cotyledons we call 
these organs. In size, form, and colouring Eucalyptus cotyledons vary with the 
species, and thus in careful hands afford valuable aid in specific determination. A 
few seeds of each species germinated in a separate pot or small box will be suffici¬ 
ent for personal study or for the instruction of a class. 
LEAVES OF SEEDLINGS. 
Soon after the cotyledons expand, the plant throws out true leaves and begins 
to build a stem. It is then what we call a seedling, and we shall rightly call it a 
seedling so long as it retains its distinctively juvenile form and aspect. This may 
be for a year or more. It is well known that many trees in thus starting their 
lives exhibit a form of foliage very different from that which they assume as they 
advance towards maturity. Lovers of the New Zealand bush will be familiar with 
examples of such dimorphism of foliage in our own indigenous flora. 
Amongst the eucalypts the percentage of species in which a distinct change of 
leaf form takes place is very large. In some species the amount of change, though 
evident, is not very great; in others the leaves of the mature or adult trees differ 
so much from those of the seedling that without previous knowledge we should 
