(R.T.B., Proc. Linn. Soc, N.S.W., 1899, p. 602, t. XLV.) Half Mahogany.

Systematic. - A good-sized tree, as far as seen, with a bark similar to that of some species of Pines. Ultimate branchlets angular. Abnormal leaves ovate, shortly acuminate, lanceolate, thin, almost membraneous, petiole slender, from 1 to 2 inches long; venation prominent, intramarginal vein removed from the edge. Normal leaves lanceolate-falcate, coriaceous, acuminate, almost 1 foot long in some cases, not shining, colour uniform on both sides, petiole rather slender, channelled above; venation very distinct in the coast trees, but finer in the inland ones, lateral veins very prominent and spreading, curved, numerous, the intramarginal vein removed from the edge. Peduncles axillary, about 1 inch long, flattened, bearing about ten fairly large flowers. Calyx tube occasionally angular, 6 lines long; operculum about 'as long as the calyx, conical, sometimes concave below the summit.

Fruit. - Large, hemispherical, to pyriform, on a pedicel of about 4 lines in length; rim quite 1 line broad; valves prominently exserted, acute or. occasionally obtuse as depicted; nearly 3 lines long, 4 lines in diameter.

These are very much like an enlarged, form of E. resini-fera, but more bell-shaped.

Habitat. - Ballina, Bungwahl, Belmore, Milton, Ashfield, Sassafras, New South Wales,

172 Eucalyptus patentinervis 256

REMARKS. The common name of "Half Mahogany" might lead one to place this species under

E. resinifera, Sm., and, no doubt, it may have been so classed in herbaria, but it differs from it in several features. The leaves of E. resinifera have "numerous fine, close, parallel, and almost transverse veins, sometimes scarcely conspicuous, the intramarginal one close to the edge." This species has a venation more like that of E. tereticornis, Sm., than of E. resinifera, Sm. The transverse veins are oblique, prominent, and spreading, and the intramarginal one removed from the edge, particularly in the abnormal leaves. The venation, therefore, shows no connection with E. resinifera, Sm., nor does it with E. pellita, F.v.M. From this latter species it also differs in the shape and size of the calyx tube, and also in the fruits. The timber is specifically light, and of a pale-red colour. The odour is quite unlike that exhaled from any other Eucalyptus. The fruits are characteristic, and the bark is close and compact. It is well distributed in the Coast district, extending from the Queensland border to Illawarra. Since this species was described, we have seen a specimen in the National Herbarium, Melbourne, labelled E. Kirtoni, by Baron von Mueller, which much resembles, and, no doubt, is this species; but, as no proper description of E. Kirtoni was ever published, and in view of the scientific data now recorded we have decided to let our name stand, purely for the sake of scientific precision.

Mr. Maiden joins issue with us in retaining this name, but admits (Crit. Rev. Euc. Vol. iii., p. 200) that " Mueller's description is unsatisfactory as measured by modem standards."

ESSENTIAL OIL. - Leaves and terminal branchlets for distillation were obtained from Belmore, N.S.W., in February, 1900. The yield of oil was 0.26 per cent. The crude oil was orange-brown in colour, was very mobile, and had a secondary odour resembling that of citral. The presence of this aldehyde in the oil was proved by extracting it with acid sodium sulphite, and preparing its characteristic naphthocinchoninic acid. Phellandrene could not be detected, nor was conclusive proof obtained of the presence of pinene. The low specific gravity of the first fraction, its high lævo-rotation, together with its boiling point, suggested the presence of limonene, but attempts to form the characteristic tetra-bromide were not successful, nor were the reactions for cymene obtained. At present the identity of this terpene remains undecided. Cineol could not be detected in the oil. A good quantity of the sesquiterpene was present, 20 per cent, distilling between 260-2700 C. Free alcohols occur, and these gave the oil a pleasant odour. Esters were not pronounced.

The crude oil had specific gravity at 150 C. = 0.8735; rotation aD - 15.2°; refractive index at 200 = 1.4891, and was insoluble in 10 volumes 80 per cent. alcohol. The saponification number for the esters and free acid was 6.2.

A portion of the oil was acetylated in the usual way when the saponifi-fication number had risen to 63.3, suggesting the presence of nearly 16 per cent. of free alcohol, if calculated for the C10H18O molecule.

On rectification, 2 per cent, distilled below 1740 C. (corr.). Between 174-1790, 34 per cent, distilled; between 179-2450, 27 per cent. came over, and between 245-2730, 24 per cent, distilled. Thus 13 per cent. remained in the still, boiling above 271° C. The fractions gave the following results: -

First fraction, sp. gr. at 150 C.

0.8519;

rotation aD

-

23.4°.

Second

"

"

"

=

0.8600;

"

not taken.

Third

"

"

"

=

0.9035;

"

"

The above sample was stored in the dark, and in November, 1919, was again analysed. Very little alteration had taken place during the nineteen years the oil had been kept, except that the specific gravity had increased a little, and the optical rotation had diminished about 5 degrees. 47 per cent. distilled below 190° C. The crude oil and the rectified portion gave the following results: -

Crude oil, sp. gr. at 150 C.

=

0.8832; rotation aD - 9.5; refractive index at 200 = 1.4891.

Rectified portion

"

=

0.8544; rotation aD - 22.4°; refractive index at 200 = 1.4807.

The cineol was determined by the resorcinol method in the rectified portion; when calculated for the crude oil, the result was only 1 per cent. It is thus evident that cineol was practically absent in the oil of this species, as were also other absorbable bodies,

Plate LXXXI.

172 Eucalyptus patentinervis 257

Eucalyptus Patentinervis, R.T.B. A Mahogany