Chemistry of Essential Oils

(Tuis.) #1

MYKTACE^ 347


is of medium size with a ' Peppermint' bark, opposite, sessile, cordate-
lanceolate ' sucker ' leaves, medium-sized lanceolate normal leaves, small
hemispherical fruits with a truncate or depressed rim, and the leaves
yielding a particular oil.
" As far as our researches go, trees having these characteristics do not
appear to occur in Tasmania, where the name was originally ascribed to
this species. Thus the trees going under the name of Eucalyptus amyg-
dalina in Tasmania and Eucalyptus amygdalina in Victoria and New
South Wales are not the same.
" As, however, the name has become so interwoven with the euca-
lyptus literature of Victoria and New South Wales in connection with
the economics of the tree found there, it is now almost next to impossible
to supersede the name of the tree of the Eastern States, or at least
without adding to the already long nomenclature of the genus.
" That the latter is not Labillardier's tree we are firmly convinced,,
and on the following grounds :—
"1. The plate of Eucalyptus amygdalina of Labillardier in his Plant*
of New Holland depicts the Tasmanian Eucalypt, and certainly not the
mainland one.
" 2. The ' sucker' leaves of the former are petiolate, alternate, and
the latter opposite, sessile, cordate, obtuse.
" 3. The normal leaves of the former are smaller, and narrower.
" 4. The fruits of the Tasmanian tree are practically identical in
shape with those of Eucalyptus dives Sch., and not hemispherical like
those of the mainland Eucalyptus amygdalina.
" 5. The oil of the Tasmanian tree closely approaches in chemical
composition that of Eucalyptus dives Sch.
" Labillardier's name for the Tasmanian tree must, of course, stand,,
as that has priority, and to us it appears too late in the day to alter the
specific appellation of the other ; but if a systematic distinction is neces-
sary in future, we would suggest that it might be known, to botanists at
least, as Eucalyptus amygdalina, var. Australiana. This form is faith-
fully figured by Mueller in his Eucalyptographia, and is also illustrated
by us in our work Eucalypts and Their Essential Oils (p. 168). The
varieties recorded by Bentham, we find, belong to Eucalyptus Eisdoni
rather than Eucalyptus amygdalina.
"Essential Oil.—Material of this species—known as 'Black Pepper-
mint '—was received from various localities in Tasmania, collected at
various times of the year, in order that definite conclusions might be
formed as to the specific differences between the oil of Eucalyptus amyg-
dalina of Tasmania and that of the. tree known in New South Wales
and Victoria as Eucalyptus amygdalina. Although the general character
of the oil of the Tasmanian tree places it in the ' amygdalina group' of
these oils, yet it differs considerably from that of the New South Wales
form, and more closely approaches in constituents and physical pro-
perties the oil of Eucalyptus dives, with the exception that the Tas-
manian Eitcalyptus amygdalina contains a little more eucalyptol than.
does that of Eucalyptus dives. Commercially the oil could be utilised
for purposes similar to those to which that of Eucalyptus dives is put,
but it would not pay to submit it to fractional distillation in order to-
separate the eucalyptol portion, as is now often carried out with the oil
of the New South Wales form, any more than it would pay to do so-
with the oil of Eucalyptus dives. The yield of oil of the New South-

Free download pdf