(Sieb., in DC. Prod., iii, 218.) White-top Peppermint or Paver White Gum.

Systematic. - A fairly tall tree. It has a hard, black bark on the lower part of the trunk, but smooth on the upper portion of the tree. Abnormal leaves thin, sessile, or almost perfoliate, much resembling those of the "Messmate" E. phellandra, opposite, narrow, about 3 to 4 inches long, marginal vein slightly removed from the edges. Normal leaves lanceolate, narrow, generally about

6 inches long, membraneous, on a petiole of about 1 inch long; venation not prominent, intramarginal vein removed from the edge, lateral veins oblique, spreading. Flowers very numerous, up to thirty, on axillary peduncles. Calyx tube turbinate, or truncate spherical, small, 1 line long, tapering to a long filiform pedicel; operculum obtuse.

Fruit. - Numerous, small, pilular, on filiform pedicels; rim thin, contracted; valves not exserted; 2, rarely 3, lines in diameter.

.1 fruit with little variation in shape and often more globular than depicted here.

Habitat.- -On river banks and mountain ranges of the coast district, but preferring banks of creeks, New South Wales.

REMARKS. This Eucalyptus has had a "battledore-and -shuttlecock" experience at the hands of systematists since its naming by Sieber in "De Candolle's Prodromus," iii, 218, 1828. Bentham, B.F1., iii, p. 203, gives its varietal rank under E. amygdalina. Labill., and Mueller, in "Eucalyptographia," synonymises it altogether under that species. This action Or. Woolls strongly opposed, for he states (" Flora of Australia," p. 239): " No one who has had an opportunity of examining both trees in a living state would suppose them to be allied, as they vary so much from each other in bark and habit," and to this we would add morphological and physical properties. Next Deane and Maiden also place it as a variety of E. amygdalina, Proc. Linn. Soc, N.S.W., Vol. 20, p. 603. Maiden later, however, synonymises it under E. amygdalina, "A Critical Rev.," Vol. I, p. 151, but restores it to specific rank (Proc. Roy. Soc. N.S.W., Vol. 51, p. 461), placing our E. Australiana as a synonym. Dr. Woolls was familial with the tree in the field under the common name of "River White Gum," and Bentham reproduces this name for it under Woolls' authority. Sieber travelled where the "River White Cum" now occurs, and the attempt made to place E. Australiana as Sieber's tree is difficult to understand, as there is nothing to show that that author ever travelled into what was in 1834 remote and inaccessible parts of the Colony, and so the chances are all in favour that he never saw this latter tree, as it is only within the last few years that the district has been opened up; and. besides, Sieber's description does not match E, Australiana, but it does match what has been known and is still recognised as the " River White Gum" of Woolls. Sieber's E. radiata is acknowledged in our first edition, and no new data appear to us to have been brought to light to warrant our placing E. Australiana, which has a Peppermint bark, as a synonym of this smooth bark tree - now Maiden's E. numerosa. (Proc. Roy. Soc, N.S.W., Vol. LI). Sieber's E. radiata we regard as the "River White Gum."

ESSENTIAL OIL. Leaves and terminal branchlets for distillation were obtained from Monga, N.S.W., in September, 1898. The yield of oil was 1.88 per cent. The crude oil was almost colourless, and had a peppermint odour due to the presence of piperitone. It contained much phellandrene, but pinene was only detected in small amount. Only a very small quantity of cineol was found in the portion distilling at near the boiling point of that constituent.

A close agreement is noticeable between the oil of this species and that of E. dives, the only apparent differences being that the pinene was more pronounced in the oil of E. radiata than in that of E. dives, and contained less piperitone, consequently the oil commenced to distil at a lower temperature. Esters were not pronounced, and crystallised eudesmol was not detected.

The crude oil had specific gravity at 150 C. = 0.8747; rotation aD - 65.1°; refractive index at 200 = 1.4806, and was insoluble in 10 volumes 80 per cent. alcohol. The saponification number for the esters and free acid was 4.4.

On rectification, 2 per cent, distilled below 1620 C. (corr.). Between 162-1830, 58 per cent, distilled; between 183-2040, 22 per cent. came over, and between 204-2350, 13 per cent, distilled. These fractions gave the following results: -

Material of this species for distillation was also obtained from Wingello, N.S.W., in September, 1900. The yield of oil was 1.2 per cent. The oil was practically identical with that previously obtained from Monga, except that rather more phellandrene was present, and consequently the rotation to the left was somewhat higher. The following results show this clearly.

The crude oil had specific gravity at 150 C. = 0.8695; and rotation aD - 77.7o Per cent, distilled between 166-1830; 15 per cent. between 183-2240, and 13 per cent. between 224-2400.

The saponification number for the esters and free acid was 2.8.

Material for distillation was obtained from Hill Top, N.S.W., in November, 1919. The yield of oil was 2.9 per cent. The crude oil was but little coloured, had a peppermint odour, and consisted principally of phellandrene, together with small quantities of piperitone and piperitol.

The crude oil had specific gravity at 150 C. = 0.8643; rotation aD - 5975°; refractive index at 200 = 1.4777, and was insoluble in 10 volumes 80 per cent, alcohol. The saponification number for the esters and free acid was 8.4, and after acetylation 35.8.

On rectification, 73 per cent. distilled below 1800 C.; between 180-2000, 18 per cent. came over, and between 200-2650, 6 per cent. distilled. The fractions gave the following results: -

Absorption by normal sodium sulphite showed that 5 per cent. of the crude oil consisted of piperitone.

For the investigation of the alcohol piperitol, see the article on that substance in this work.