(Labill. in Pl. Nov. Holl., ii, 14, t. 154.) Black Peppermint.

Systematic. - An average forest tree in height. The bark is characteristic of the "Peppermint" variety, as illustrated in this work. The abnormal leaves small, narrow, lanceolate, about 1 inch long, shortly petio-late or sessile, gradually becoming alternate, sometimes three in a whorl; venation well marked, marginal vein removed from the edge, broad ovate to lanceolate, up to 3 inches long and 1/2 inch broad, shortly petiolate or sessile, cordate. Normal leaves almost invariably lanceolate, varying in size according to locality, narrow and small to medium broad, and up to 3 or 4 inches long. Inflorescence in axillary clusters on flattened peduncles. Buds clavate; calyx pyriform; operculum rounded or flattened.

Fruit. - Shortly pedicellate, hemispherical, sometimes pear-shaped; rim thick, slightly domed, shiny or not; up to 3 lines long, and the same in diameter.

The nearest approach to this capsule in shape is that of E. dives; it also somewhat resembles E. Australiana, but with care can be distinguished by the rim.

Habitat. - Tasmania.

REMARKS. - Since first recorded by Labillardiere from Tasmania a number of species described from the mainland by various authors, have from time to time been regarded by some later systematists as synonyms. The list is too long to be published here, but will be found in botanical works and papers bearing on Eucalypts. Our investigations almost invariably go to show that most of these Eucalypts are worthy of specific rank. In our paper on the Eucalypts of Tasmania and their Essential Oils (Roy. Soc. Tas., 1912) under this tree, we mention the fact that "as far as our researches go, Labillardiere's species does not appear to occur on the mainland of Australia."

ESSENTIAL OIL. - Material of this species, known as "Black Peppermint," was received from various localities in Tasmania, and collected at various times of the year, in order that definite conclusions might be secured as to the specific differences between the oil of E. amygdalina of Tasmania, and that of trees known in New South Wales and Victoria as "Narrow-leaved Peppermint." The character of the oil of the Tasmanian tree places it in the pronounced " phellan-drene group" of these oils, and it thus differs considerably from that of the Australian form. It more closely approaches, in constituents and physical properties, the oil of E. dives, with the exception that the oil of the Tasmanian E. amygdalina contains a little more cineol than does that of E. dives. Commercially the oil-could be utilised for similar purposes to those for which that of E. dives is employed, but it would not pay to submit it to fractional distillation in order to separate the cineol portion, any more than it would pay to do so with the oil of E. dives. The yield of oil of the New South Wales form is almost twice that obtained from the Tasmanian trees, and even E. dives yields a greater quantity of oil than does E. amygdalina of Tasmania. The oil of the Tasmanian

E. amygdalina differs from that of the New South Wales form in that it contains much less cineol, has a very high lævo-rotation, contains much more phellan-drene, and is much less soluble in alcohol. The odour of the oil is also much less aromatic. The terpineol in the oil of the Australian form is responsible for this more pronounced aromatic odour and greater solubility.

The following tabulated results give the general characters of the crude oils from three consignments, collected at the several localities, and on the dates given: -

The cineol was determined by the resorcinol method, and although this would seem to indicate the presence of an increased amount of that constituent, yet a phosphoric acid determination in the mixed oils gave a result of 16 per cent, cineol.

The Nubeena sample contained less high-boiling constituents than did the Hobart material, and consequently had a lower specific gravity. It also contained more cineol.

On rectification, nothing distilled below 1740 C. (corr.) with either sample. The Hobart (16th April, 1920), oil gave 57 per cent, distilling between 174-195° C, and 37 per cent, between 195-255°, mostly between 230-240°. The Hobart sample (15th May, 1912) gave 63 per cent, between 174-195°, and 32 per cent, between 195-245°. The. Nubeena sample gave 83 per cent, distilling between 174-195°, and 10 per cent, between 195-266°. These fractions gave the following results: -

The high-boiling portions of these oils contained a considerable quahtity of piperitone, as is the case with E. dives; thus the temperature did not rise much above 255° C. ____________

Besides the above material sent by the Museum collector, we also received the leaves of the "Black Peppermint," from Scottsdale, Tasmania, forwarded by Mr. A. H. Higgs (6th March, 1912). This material gave a yield of oil equal to 2.32 per cent.

The crude oil had the following characters: - Specific gravity at 150 C. = 0.8765; rotation aD - 42.9°; refractive index at 200 - 1.4796; soluble in 5 volumes 80 per cent, alcohol; had saponification number for esters and free acid = 2.9, and contained 20 per cent, cineol, by the resorcinol method.

On rectification, 80 per cent. distilled between 174-1930 C, and 13 percent, between 193-2620. The fractions gave the following results: -

The oil distilled from the leaves of the "Black Peppermint" of Tasmania, E. amygdalina, from material all over the island, is thus seen to have considerable uniformity in composition.

The results of this investigation were published by us in the Proc Roy. Soc, Tasmania, October, 1912.