712 BOTANY OF THE INTERIOR OF NEW SOUTH WALES, 



about Bathurst and Orange, &c, where it is also called Brittle 

 Gum and Brittle Jack. In general appearance E. tereticornis 

 and E. dealbata are wonderfully alike, both in bark and foliage, 

 even in detail. The woods are also very similar, though that of 

 E. dealbata is softer, and not considered so lasting; still this is 

 often attributed to the fact that one grows on a good flat, and 

 the other on a ridge with shallow soil. 



E. dealbata is the smaller tree, and out west will often grow in 

 mallee-form — that is, with 8 or 10 stems from one root, and from 

 12 to 15 feet high, though it never forms extensive scrubs like 

 typical mallee, and the wood is not so tough. 



The opercula of E. tereticornis are generally long and pointed, 

 but in R. dealbata they present more variation than those of most 

 Eucalypts, being sometimes quite pointed, and at others almost 

 hemispherical, varying in length from about half an inch to two 

 lines. Taking the fruits of E. tereticornis, it is found that they 

 are pedicellate and domed, while those of E. dealbata are almost 

 sessile and truncate, and therein, together with a difference in the 

 opercula, seem to lie the chief distinguishing marks; yet in the 

 districts where both trees grow it is undeniable that these 

 conditions to some extent seem to graduate from one to the other, 

 as it is possible to find trees with fruits both sessile and domed. 

 Ignoring intermediate stages, and taking E. tereticornis of Parra- 

 matta on the one hand, and E. dealbata of Nymagee on the other, 

 it would be at once concluded these were two different species. 

 The idea suggested by this hypothesis is that possibly they are 

 actually distinct, and only appear to graduate from one to the 

 other when growing in the same neighbourhood. Apart from 

 the fruits, and viewing the trees in the field where both grow, it 

 seems quite impossible to distinguish the species with certainty 

 if their situation is not taken into consideration; but with local 

 knowledge the tree on the high land is separable from the one 

 in the valleys or on the flats. 



Of course it is well-known that Forest Red Gum, in some 

 situations, is scarcely distinguishable from E. rostrata (River Red 

 Gum) except by the fruits; still field observation has satisfied 



