(H.D. & J.H.M., Proc. Linn. Soc, N.S.W., 1899, p. 448, t. XXXVIII.) Paddy's River Box, Camden Woollybutt.

Systematic. - A medium-sized tree, with a rough, somewhat "Box"-like bark. Abnormal leaves linear-lanceolate, slightly cordate, barely stem clasping, sessile, and opposite, bright green in colour, of similar tint on both sides. Normal leaves alternate, narrow lanceolate, often falcate, thickish, of equal colour on both sides; venation not prominent, intramarginal vein at some distance from the edge. Umbels axillary, with short, scarcely flattened peduncles, and pedicels absent, or nearly so. Buds small, the operculum and calyx of approximately equal size, the former but very slightly conical, up to eight in the head, but perhaps five on the average.

Fruit. - Hemispherical, slightly dilated at the rim, which is well defined; valves usually three, but rarely four, scarcely exserted, 2 to 3 lines in diameter.

These so much resemble those of E. Rodwayi that some systematists have confounded the two. They are also very close in shape to E. aggregata and E. acaciæformis.

Habitat. - Confined to the counties of Camden and Argyle, New South Wales, as far as known at present. Prefers swampy or low-lying land, or the banks of streams; Mittagong, Bowral, and Moss Vale, New South Wales.

REMARKS. - Bentham thought this species had an affinity with E. viminalis, but, except in the abnormal and mature leaves, the affinity does not appear to be marked. Its narrow abnormal leaves and small fruits should prevent its confusion with E. Bridgesiana, R.T.B. It is a very distinct species in the field, and could not be confused with other Eucalypts. The odour of the leaves when crushed at once distinguishes this species from all others with the exception of that of E. acervula. The remarks of the authors of the species (loc. cit.) on E. diversifolia apply to their E. rubida, and not to this species.

ESSENTIAL OIL. - In the year 1900, the discovery was made that the oil of Eucalyptus Macarthuri was of quite an exceptional character, in that it consisted very largely of geranyl-acetate and free geraniol. (See paper by one of us, Proc. Roy. Soc, N.S.W., Nov., 1900.) Since that time a considerable amount of work has been done upon the oil of this species, and it has always been found to be in agreement with the results originally published. The species has become of importance for the production of an oil for perfumery purposes, and is now being cultivated in Victoria. The species grows to a large size and has a thick aromatic bark, which also produces an essential oil similar in composition with that from the leaves. (See Proc. Roy. Soc, N.S.W., October, 1916.) The oil is present in sufficient quantity in the bark to allow it to be profitably distilled. The "suckers" from the stumps of the fallen trees grow rapidly, and produce an oil equal in value to that from the mature leaves, so that the process of distilling oil from the bark is not so wasteful as might at first sight appear. The bark oil, however, does not contain crystallised eudesmol, which substance is such a pronounced constituent in the leaf oil. The higher-boiling portions of the leaf-oil contained sufficient eudesmol to cause the third fraction to crystallise to a solid mass soon after distilling. Neither phellandrene nor cineol occur in the oil of this species, the small amount of terpene being dextro-rotatory pinene.

The results from a very large number of analyses on the oil of this species show that 60 per cent, of geranyl-acetate, saponifiable in the cold with two hours' contact with alcoholic potash, is the minimum at any time of the year. The oil of E. Macarthuri seems to follow the general rule for Eucalyptus oils by containing less terpene during the winter months, with a corresponding increase in ester. The oil from abnormal leaves contains even more ester than does that from the mature leaves, while that from leaves of two years old seedlings is also richer in geranyl-acetate than the oil from old leaves.

The crude oils are usually red in colour; as explained previously this red colour is due to the free acid in the oil attacking the iron of the still, and this, acting on the phenols, causes the oil to become red. The free geraniol in the oil was less when the ester content was high, and greater when the amount of ester approached the minimum of 60 per cent. When the oil was distilled directly under atmospheric pressure, the ester was partly decomposed. (See the article in this work on "Geraniol and its acetic acid ester.")

Plate LXXVII.

Eucalyptus Macarthuri, H.D. & J.H.M

Camden Woolly Butt.

Oil from the Leaves. - Leaves and terminal branchlets for distillation were obtained from Wingello, N.S.W., in October, 1900. The yield of oil was 0.12 per cent., 500 lb. of leaves and branchlets giving 9 ounces of oil. This appears

Plate LXXVIII.

[Photo.] [M. F. Connelly].

Eucalyptus Macarthuri (D. & M ) Paddy's River Box

Near Wingello, N.S.W.

to be a minimum yield, as the average more nearly approaches 02 per cent. The crude oil was red in colour, and consisted principally of the ester geranyl-acetate, free geraniol, and eudesmol, with some pinene.

. The crude oil had specific gravity at 150 C. = 0.9245; rotation aD + 3.6°; refractive index at 20° = 1.4706, and was soluble in 1 1/2 volumes 70 per cent. alcohol. The saponification number for the esters and free acid was 173.4, equal to 60.6 per cent. of geranyl-acetate. The dextrorotation of the crude oil was partly due to the activity of the eudesmol.

On rectification, 1 per cent, distilled below 172° C. (corr.). Between 172-2190, 10 per cent. distilled; between 219-2290, 63 per cent. distilled; the temperature then rapidly rose to 266°, a few drops only being obtained. Between 266-2820, 16 per cent, distilled, which fraction soon became solid. These fractions gave the following results: -