650 J^JUTKS UN THK NATIVK FLOKA OF K. S. WAbES^ ix., 



Bomcwluit limited extent east and west, and present [xjssibilities of 

 inigTation to the places wheie it now occurs ni this State, it seems 

 probable that nuich of this distribution has occurred under condi- 

 tions of present-day topography. 



Melaleuca bracteata is the common Tea-tree along the creeks 

 north-east of Boggabri, growing in groups or clusters up to 20 

 feet high, and flowering late in November. The clustering habit 

 of these trees causes a bending over and bunching of the heads, 

 which render them useful for shade purposes. (Plate Ixvii.) 



The presence of such trees as Acacia pendula (Myall), and 

 Eucalyptus popuUfolia (Bimble or Shiny-leaved Box), east of 

 Boggabri, shows that typical western conditions come eastward to 

 this locality, which marks a point on the eastern margin of the 

 habitat of both these species. 



Ficus rubiginosa, usually a moist-climate or coastal tree, is well 

 established on the dry summit of Barber's Pnmacle, and on other 

 hills. 



The selective equalities of plants, wdien seeking suitable conditions 

 for subsistence, are exemplified in the Eucalyjjfs and other genera 

 around Boggabri, and accord with what may be seen in a similar 

 climate elsewhere in this State. Certain trees find it necessary that 

 their roots should reach abundant moisture, while others have 

 adapted themselves to subsist where the soil-moisture is slight in- 

 deed. Taking the three conditions of moisture at Boggabri, viz., 

 that of the river-banks, the alluvial flats, and the hills, it is found 

 that the river-banks are occupied by Eucalyptus roslrala, while the 

 flats are covered with E. popuUfolia, E. Woollsiana, E. melliodora 

 and E. terelicornis, the hills and even slight ridges being the home 

 of E. albenS) E. crebra, E. melanophloia, E. dealbata and E. viri- 

 dis. 



Tlie local Casuarinas have distributed themselves in the follow- 

 ing manner: — 6'. Cunninghamiana along the rivei'-banks, C. Cam- 

 bagei on tlie flats, and C. Luehmanni on the elevations. Other 

 genera descriminate in a similar manner. 



From a study of this distribution, and adaptation to environ- 

 ment, it is easy to conceive how a process of evolution may be 



