(A. Cunn., in Mitch. Trop. Aust., 339, name only.) Red Flowering Ironbark.

Systematic. - A tree occasionally as high as 100 feet. Bark persistent, rough, black, very deeply furrowed. Abnormal leaves similar in shape to the normal ones, only slightly smaller. Normal leaves lanceolate, slightly falcate, under 6 inches long; venation indistinct, lateral veins fine, spreading, intramar-ginal vein removed from the edge. Penducles slender, axillary, about 1 inch long. Flowers fairly large, about six in the umbel, mostly red but occasionally white. Calyx about 3 lines long, elongated, on a slender pedicel from 3 to 4 lines long, 3 lines in diameter; operculum equal in length to the calyx, conical, obtuse.

Fruit.-Globular, truncate, contracted at the edge, the pedicel lengthening after flowering; rim concave after the removal of the primary one, which becomes detached when the capsule ripens, this latter feature readily distinguishes the fruits from most other species; valves inserted; 4 lines in diameter.

A deciduous secondary rim is found only in this and in a few other species, such as E. leucoxylon, E. caerulea, and sometimes E. melliodora.

Habitat. - Coast district of New South Wales, Queensland and Victoria.

REMARKS. - Cunningham's name of E. sideroxylon is retained for this tree, which was first mentioned in Mitchell's "Tropical Australia," p. 339. To Dr. Woolls (Proc. Linn. Soc, N.S.W., p. S56) is due the credit of proving conclusively that both Mueller and Bentham included two distinct trees under the name of E. leucoxylon, i.e the South Australian "White Cum" and this "Red-flowering Ironbark." They differ in bark, timber, flowers, fruits and anthers, and probably chemical constituents. This Ironbark is very constant in specific characters throughout its extensive range in New South Wales and Victoria. The colcur of the flowers, however, vary from cream to light pink. The bark is also black and friable.

ESSENTIAL OIL. - Leaves and terminal branchlets for distillation were obtained from Liverpool, N.S.W., in December, 1900. The yield of oil was 0.75 per cent. The crude oil was of a reddish-yellow colour, and had an odour resembling the cineol-pinene class of Eucalyptus oils. The usual amount of volatile aldehydes for oils of this group was present. The oil was rich in cineol; pinene was present, but phellandrene was absent. An aldehyde was present in the higher boiling fraction, together with the sesquiterpene. The rectified oil was of good quality for a cineol oil, and was slightly coloured yellow, a character traceable to the influence of the phenols. In general characters the oil was not in entire agreement with those of the "Ironbarks" generally.

This species has been worked for its oil to some extent in the Bendigo District of Victoria, where the yield usually exceeds 1 per cent.

The crude oil had specific gravity at 150 C. = 0.9227; rotation aD + 1.9°, refractive index at 200 = 1.4668, and was soluble in 1 1/4 volumes 70 per cent. alcohol. The saponification number for the esters and free acid was 2.5.

On rectification, 1 per cent. distilled below 1620 C. (corr.) Between 162-1830, 91 per cent. distilled; between 183-2400, only a few drops came over, and between 240-2550, 3 per cent. distilled. These fractions gave the following results: -

The cineol, determined by the phosphoric acid method in the rectified portion, gave 66 per cent. of that constituent, indicating about 60 per cent. in the crude oil (O.M.).

Material of this species for distillation was also obtained from Condobolin, N.S.W., in March, 1901. The oil was practically identical with that distilled from the Liverpool trees, and contained the same constituents in practically the same amounts. The yield of oil was 0.51 per cent. The specific gravity of the crude oil was 0.9189, and the optical rotation aD + 3.2°. The cineol determined by the phosphoric acid method in the crude oil was 57 per cent. (O.M.).

Material for distillation was also obtained from Narrabri, N.S.W., in July, 1901. The oil was practically identical with the above samples, contained similar constituents in agreeing amounts, and was equally rich in cineol. The yield of oil was 0.49 per cent. The specific gravity of the crude oil was 0.9201, and optical rotation aD + 1.4°. The cineol, determined by the phosphoric acid method in the crude oil, was 58 per cent. (O.M.). The crude oil was soluble in 1 1/4 volumes 70 per cent, alcohol.

It will be seen from these results that the oil of this species shows a constancy in composition wherever the trees are growing, and is thus a well stabilised species.

In the samples recorded above, the oils were distilled from normal leaves of old trees, and the yields of oil are consequently less than would be obtained from young material or from leaves of abnormal growth. This is a peculiarity shown with many species of Eucalypts, and numerous instances of this are given in this work.

The above samples were mixed together and stored in the dark, and in August, 1919, the oil was again analysed. Not much alteration had taken place during the 20 years the oil had been kept, with the exception that the cineol had increased a little in amount. The crude oil and the rectified portion gave the following results: - 90 per cent. distilled below 1900 C.

The cineol was determined by the resorcmol method in the rectified portion and calculated for the crude oil; the result was 78 per cent. By the rapid phosphoric acid method it was 65 per cent. when calculated for the crude oil. Terpineol was detected in the rectified portion.

Plate XXXII.

Eucalyptus Sideroxylon. A. Cunn Red Flowering Ironbark