202 



crystals had apparently grown. The identity of this alcohol is thus not so com 

 pletely shown as was the case with the oil of E. Rossii, for instance, which was 

 changed into the crystalline form on distillation under reduced pressure. (See 

 under that species, and also the article dealing with eudesmol.) 



705. Eucalyptus Risdoni. 



(Hook, f., in Hook. Journ., vi, 477, and Fl. Tasm., i, 133, t. 24.) 

 Risdon or Drooping Gum. 



Systematic. A small or medium-sized tree, with a smooth, deciduous 

 bark, and glaucous foliage, inflorescence, and branchlets. Leaves very variable 

 in size and shape, either opposite, sessile, connate, ovate, cordate, acuminate, 

 thick, with recurved margins, about ij inch long, or alternate,, ovate-lanceolate, 

 lanceolate and sometimes measuring 6 inches long, occasionally shining ; 

 venation fairly distinct, lateral veins oblique, spreading, distant ; in the lanceolate 

 leaves the tendency is in the direction of phellandrene oil venation ; intramarginal 

 vein well removed from the edge and showing a looping arrangement. Peduncles 

 axillary, 3 to 4 lines long, terete or angular, bearing six to nine fairly large flowers. 

 Calyx tube pyriform, 3 lines in diameter, 5 lines long; operculum depressed, 

 hemispherical, shortly acuminate. 



Fruit. Sub-globose, truncate, sometimes con- 

 tracted at the orifice, or pear-shaped ; 

 rim truncate to countersunk ; valves 

 not or scarcely exserted ; 4 lines in 

 diameter. 



These fruits could not easily be confounded with 

 any others, although those with the countersunk rim 

 resemble E. obtusiflora. 



Habitat. Southern Tasmania. 



REMARKS. The life history (if one may use the expression in this connection) of this Eucalyptus is 

 identical with that of the mainland species E. dives, Schau., in that it flowers and fruits when quite a small shrub, 

 and when all its leaves are in the opposite, sessile, and cordate form. Singularly enough, both Hook. f. and Schauer 

 founded their species on the shrubby form only, and in the case of E. dives it was not till shown by this research, 

 that the mature trees were identified. Hook. f. figures and describes (loc. cit.) what has since been shown to be the 

 primary stage of growth of his species, the mature trees of which are recorded by Bentham in his " Flora Austra- 

 liensis," iii, 203, as var. data on material collected by Gunn. The dried material of the early and mature forms of 

 this tree, when compared, would easily mislead one not acquainted with the trees in the field. " Mueller unites 

 E. Risdoni altogether with E. amv?.dalina," but our results agree with those of J. D. Hooker and Oldfield, and in 

 no way do we see so close an affinity between these two trees. 



ESSENTIAL OIL. The results obtained with the oil of E. Risdoni were 

 recorded in the first edition of this work. The yield of oil then obtained was 

 1-35 per cent. ; saponification number for ester and free acid = 27-1 ; cineol 



