170. Eucalyptus aggregata. 



(H.D. & J.H.M., Proc. Linn. Soc., N.S.W., 1899, P- 6l 4. I'l- XLIX.) 



Black Gum. 



Systematic. Usually small, gnarled trees, with a trunk of 12 to 18 inches or 

 even 2 feet in diameter. Abnormal leaves quite glabrous, oval to nearly oblong, 

 strictly opposite, up to i inch long, the margins undulate, mucronate, with a short 

 point. Normal leaves lanceolate, undulate, equally green on both sides, scarcely 

 shining, on the average probably 4^ inches long and i inch broad ; intramarginal 

 vein considerably removed from the edge, other veins few, but conspicuous, very 

 oblique. Buds usually four to six in the umbel ; operculum and calyx tube 

 about equal, and both tapering towards a. point, the operculum being nearly 

 conical. 



Fruit. Hemispherical in shape, small and some- 

 times, owing to the shortening of the pedi- 

 cels, so clustered together as to form a 

 dense head, hence the specific name ; with 

 a well defined sharp-domed rim ; three or 

 four"- well exserted valves; not exceeding 

 i| of an inch in diameter. 



Habitat. Alluvial flats, following watercourses or depressions. 

 .Usually found in damp situations. Braidwood and 

 Rydal, New South Wales. 



REMARKS. In the Proc. Roy. Soc., Tasmania, 1914, p. 30, J H Maiden claims that this is identical with 

 E. Rodwayi, a determination quite at variance with data we have obtained from each. 



ESSENTIAL OIL. Leaves and terminal branchlets for distillation were 

 obtained from Pagan's Creek, Little River, Braidwood, N.S.W., in October, 1898. 

 The yield of oil was small, 394 Ib. of leaves and branchlets giving only 2.\ oz. of 

 oil, equal to 0-04 per cent. The crude oil was light orange-brown in colour, was 

 very mobile, and had a somewhat rank odour, with but little resemblance to 

 ordinary Eucalyptus oil. It contained a somewhat large amount of pinene, 

 which was dextro-rotatory ; this terpene was proved by the formation of the 

 nitrosochloride, and other tests. Cineol and phellandrene both appeared to be 

 absent. The principal constituent was an ester, the alcohol of which was amyl- 

 alcohol, combined with a solid acid, which has been named eudesmic acid. 



The crude oil had specific gravity at 15 C. = 0-956; refractive index at 

 20 = 1-5005 ; and was insoluble in 10 volumes 80 per cent, alcohol. The saponi- 

 fication number for the esters and free acid was 112-2. 



On rectification, i per cent, distilled below 156 C. (corr.). Between 

 156-164, 26 per cent, distilled; between 164-245, 12 per cent, came over, and 

 between 245-292, 22 per cent, distilled. The remainder when removed from the 

 still became crystalline on cooling. The fractions gave the following results ; 

 First fraction, sp. gr. at 15 C. := 0-8660 ; rotation a D + 23-5, 

 Second ,, ,, ;, = 0-8769; ,, not taken, 



Third ,, ,, = 0-9868; 



