(Labill., in Pl. Nov. Holl., ii, 126, t. 151.) Manna or White Gum.

Systematic - Sometimes a very large tree, probably the largest of New South Wales Eucalypts. Bark smooth, decorticating in long strips, or rough and dark-coloured. Abnormal leaves sessile, cordate-lanceolate, acuminate. Normal leaves lanceolate, mostly under 6 inches long; venation prominent, lateral veins oblique, spreading. Peduncles axillary, about 2 or 3 lines long, mostly three-flowered. Calyx tube hemispherical; operculum acuminate.

Fruit. - Hemispherical, shining, reddish-coloured; rim rounded; valves much expanded and well exserted; 3 lines in diameter.

The fruits of E. Dalrympleana are very much like those of this species, as also are E. pumila, E. Seeana and E. Bancrofti.

Habitat. - Tablelands of the Great Dividing Range, New South Wales; South Australia; Victoria; Tasmania; Queensland.

REMARKS. - This is one of the most widely distributed species of the Genus in Australia, as well as probably the tallest. It is moderately constant, varying only a little in specific characters, whether growing in alluvial flats, basalt (Shoalhaven), or granite (Bathurst). Occasionally the number of flowers in the umbel ranges from three up to seven, but the usual number is three. The insect markings on the bark of E. viminalis differ from those of E. hæmastoma, as they almost invariably occur in straight, horizontal lines, and not in scribbles as obtains in the latter species. E. lactea, R.T.B., has the facies of this tree in the field, so that care is required not to confound them, but the abnormal leaves are ovate or lanceolate, and not sessile as in E. viminalis.

ESSENTIAL OIL. - Leaves and terminal branchlets for distillation were obtained from Cadia, near Orange, N.S.W., in June, 1898. The yield of oil was 0.36 per cent. The crude oil was dark-coloured, and had an odour resembling the cineol-terpene oils generally. Dextro-rotatory pinene was present, and phellandrene also, and the presence of this terpene appears to be characteristic for the oil of this Eucalypt wherever found growing. A rather large amount of the sesquiterpene was also present. Cineol occurs only in fair amount.

The crude oil had specific gravity at 150 C. = 0.9162; rotation not taken; refractive index at 200 = 1.4798, and was soluble in 1 volume 80 per cent. alcohol. The saponification number for the esters and free acid was 7.9.

On rectification, 2 per cent. distilled below 172° C. (coir.). Between 172-1830, 61 per cent. distilled; between 183-260°, 18 per cent. came over, and between 260-275°, 15 per cent. distilled. These fractions gave the following results: -

The cineol, determined by the phosphoric acid method in the first fraction, was 42 per cent., indicating about 28 per cent. in the crude oil (O.M.).

Material of this species for distillation was obtained from Moss Vale, N.S.W., in March, 1899. In general characters the oil differed but little from that distilled from the Cadia material. It contained a little more phellandrene, however, and the cineol was hardly so pronounced, otherwise the differences were slight.

The crude oil had specific gravity at 15° C. = 0.9044; rotation aD + 3.7°; refractive index at 20° = 1.4796, and was soluble in 2 volumes 80 per cent, alcohol. The saponification number was 6.1.

Later, in April, 1912, material for distillation was obtained from Hobart, Tasmania, and consisted of leaves and terminal branchlets, collected as would be done for commercial purposes. The crude oil was of an olive-brown colour, fairly rich in cineol, contained pinene, and a small amount of phellandrene. Phellandrene appears to be a constant constituent in the oil of E. viminalis, and helps to distinguish the normal form from those somewhat closely related. A considerable quantity of high-boiling constituents was present, consisting largely of the sesquiterpene, consequently the oil was insoluble in 70 per cent. alcohol. The results obtained with this oil from trees growing in Tasmania, agree closely with those of the oil of E. viminalis grown in Australia, thus showing the Tasmanian trees to be identical with those on the mainland. The chemical results thus support botanical indications.

The yield of oil was 0.74 per cent. The crude oil had specific gravity at 15° C. - 0.9154; rotation aD + 4.2°; refractive index at 20° = 1.4707, and was soluble in 1 volume 80 per cent. alcohol. The saponification number for the esters and free acid was 9.5.

On rectification, the usual amount of acid water and volatile aldehydes, for oils of this group, came over below 167° C. (corr.). Between 167-173°, 22 per cent. distilled; between 173-194°, 54 per cent. distilled, and between 194-269°, 20 per cent. (the greater portion above 255° C). These fractions gave the following results: -

The rectified oil was yellowish in tint, resembling in this respect the oils of the members of the "Gum" group of Eucalypts. The cineol was determined by the resorcinol method in the portion boiling below 194° C, and when calculated for the crude oil represented 50 per cent. By the phosphoric acid method the result was 41 per cent. in the crude oil.

The Cadia sample was stored in the dark, and in September, 1919, was again analysed. The specific gravity had increased somewhat, as had also the cineol. 78 per cent, distilled below 1900 C. The crude oil and the rectified portion gave the following results: -

The cineol was determined by the resorcinol method in the rectified portion and calculated for the crude oil; the result was 62 per cent. By the rapid phosphoric acid method it was 50 per cent. when calculated for the crude oil.