251 



134. Eucalyptus Dawsoni. 



\\< I B., Proi I inn So< N.S.W., 1899, p 294, 1 XX] 

 Slaty Gum. 



Systematic. A tall tier, with ;i smooth hark. The foliage, branchlets, 

 buds, and fruits, glaucous. Abnormal leaves broadly lanceolate, <> inches long, 

 and over 3 inches wide, on a petiole over 1 inch long, very obtuse, glaucou on 

 both sides; venation distinct. Normal leaves mostly short, oblong-lanceolate, 

 \ii\ obtuse, i.nrh acuminate, occasionally reddish in colour; venation fairly 

 distinct, lateral veins not quite so marked, intramarginal vein close to the 1 

 Peduncles axillary, bu1 mostly in large terminal corymbs, exceeding the leaves. 

 Buds on \ oung trees, 3 hue- Ion-. 1 .1 lino in diameter, sessile or on short pedicels : 

 operculum hemispherical, obtuse; on mature trees, 4 to 5 lines long, 1 line in 

 diameter; calyx tube tapering into a filiform pedicel; operculum conical, acute. 



Fruit. Small, on a slender or almost filiform pedi- 

 cel, turbinate; rim thin, capsule sunk ; 

 valves not exserted; mostly 1 line in 

 diameter and under 2 lines long. 



/;/ shape they arc >i<>/ utUik E i rebra, butare always 

 glatit 



Habitat. - Mun umbo, Goulburn River, and northward, Jerry's 

 Plains .md Singleton, and Mountains west of Went- 

 wortli, New South Wales. 



REMA RKS.- Tin- 1- a well-marked species, and in the field could never b ifounded with any other 



Eucalyptus. The fruits reserabl i the narrow-leaved " Iron"bark," E. crebra, and thi leaves oi thi 



E. ovalifoHa, the Ryl tone " Red Box,' bu1 it differs from them in ever} other i &i character. The late 



Dr. Woolls was very emphatii thai thi trei should bi regarded a quite distinct from E. polyanthemos, with 

 which - had previously been contused. E. polyanthemos has a " Box" bark and other characters which 



ufficienl to differentiate it from E. Dawsoni. li i also distinct from /. o alifolia. 



ESSENTIAL OIL. — Leaves and terminal branchlets for distillation were 



obtained from Bylong, N.S.W., in October, 1898. The yield of oil was 0-18 per 

 cent. I he crude oil was of an orange-brown colour, and notably of a viscous 

 nature. This viscosity was due to the presence of an extra amount of the 

 sesquiterpene and higher-boiling bodies. The oil oxidised somewhat readily on 

 exposure, drying much in the same way as does boiled linseed oil. The firsl 

 fraction consisted largely of pheUandrene, but only a very small quantity of cineol 

 could be detected. Esters were not very pronounced, so that the oil was largely 

 a terpene one., although a considerable amount of liquid eudesmol was present. 



The crude oil had Specific gravity at 15 C. = 0-9418; refractive index at 

 20 = 1-5077, and was soluble in 1 volumes So per cent, alcohol. The light did 

 not pass well. I he saponification number for the esters and free acid was 13-3. 



On rectification, 1 per cent, distilled below 172 ('. (corr.). Between 

 172-204 , 32 pes cent, distilled; between 204-255 , only a few drops came over, 

 and between 255 275" . 38 per cent, distilled. These fractions gave the following 

 results : — 



First fraction, sp. gr. at 15 C. = 0-8697 : rotation «„ — 23-5°. 



Second ,, ,, .. = 0*9458; ,, not taken. 



