24. Eucalyptus umbra. 



(K.T.B., Proc. Linn. Sue., N.S.NY., ic)oi, p. dSj, t. XLIV.) 

 Stringybark, White Mahogany. 



Systematic. A tall tree, attaining sometimes a height of 100 feet, with 

 a dark-coloured stringy bark. Abnormal leaves opposite, sessile, cordate, ovate, 

 acuminate, thin, pale-coloured on the underside; venation more pronounced 

 on the underside, upper surface shining ; over 3 inches broad, and under 6 inches 

 long. Normal leaves lanceolate, falcate, large, up to 9 inches long and i inch 

 broad, pale-coloured on both sides, coriaceous ; vena.tion distinct, lateral veins 

 spreading, oblique; intramarginal vein removed from the edge. Flowers on 

 short axillary peduncles, six to nine in the umbel. Calyx i line long, on a 

 pedicel about 2 lines long; operculum hemispherical, shortly acuminate. 



Fruit. In the early stage, pilular and under 3 lines 

 in diameter, the rim and valves sunk, like 

 E. acmenioides and E. carnea, but in the 

 mature stage hemispherical, or inclined 

 to be pear-shaped, with a diameter of 5 

 lines, and a very thick red, truncate or 

 slightly domed rim, when the fruits much 

 resemble those of E. hcemastoma and E. 

 coriacea. 



Habitat. The Coast district north from Sydney, N S.W. 



REMARKS. The early fruits of this species have a remarkable resemblance to those of E. acmenioides, 

 Scliau., in fact, so much so. that in herbarium material, the two very probably on this character have been 

 confounded in the past. The two species differ, however, considerably in the shape, texture, colour, and venation 

 of the leaves, as well as in the mature fruits, which have a broad rim. E. acmenioides, Schau., has thin leaves, 

 with a pale uncler-surface, wlrch undoubtedly resemble those of Acmena (Eugenia as now understood), but 

 those of E. umbra are of a uniform colour on both sides, longer and broader, and with a very marked venation 

 much like that of E. patentinervis, R.T.B. The abnormal leaves are also quite distinct from those of E. acmenioides. 

 The bark is lighter-coloured. 



ESSENTIAL OIL. Leaves and terminal branchlets for distillation were 

 obtained at Gosford, N.S.W., in August, 1899. The yield of oil was 0-6 per 

 cent. The crude oil was of a light amber colour, and had an odour resembling 

 those of the pinene-cineol class generally. Pinene was present in quantity, but 

 phellandrene was absent. Cineol was also a pronounced constituent. The higher 

 boiling portions consisted largely of the sesquiterpene. and eudesmol was not 

 detected. Although resembling in general characters the oil of E. carnea, yet 

 it contained much less ester and considerably more cineol, and it thus appears 

 that these two trees are not identical species. 



The crude oil had specific gravity at 15 C. = 0-8970 ; rotation a D + 18-7 ; 

 refractive index at 20 = 1-4639, and was soluble in 5 volumes 80 per cent, 

 alcohol. The saponification number for the esters and free acid was 7-1. 



