BY DR. KAREL DOMIN. 65 



parts of rocks easily carried away by n:eans of wind, are 

 barren (or nearly so), the protected parts are timbered. 

 This everybody can observe in cases where the direction 

 of the prevailing wind^ has not been disturbed. In many 

 cases, however, there are groups of islands and then the 

 direction of wind changes according to their position, 

 and it seems at first sight impossible to find a plausible 

 explanation for the phenomenon mentioned above. I hope 

 in a special paper to deal in detail with this interesting 

 question. 



The other type of forest is the very well known ofen 

 forest, with close undergrowth of grasses and scattered 

 trees, mostly from the genus Eucalyptus, known under 

 difierent names as gums, box, stringy bark, ironbark,. 

 Moreton Bay ash, coolibah, bloodwood, etc., etc. The 

 other trees growing in the open forest are not only botani- 

 cally but also in their ecology very different from scrub 

 trees, and these two forest associations have no similiarity 

 at all. Forest grows und^r conditions insufficient for vine- 

 scrub, either from the character of the soil or the small 

 rainfall. Most interesting is the contact between the open 

 forests and vine-scrubs in the Northern and Central 

 portion of Queensland. The line of demarcation between 

 them is most distinct, a phenomenon which is unique in the 

 whole world. I had opportunities to examine these rela- 

 tions in many places and found that the reasons for this 

 most decided demarcation are different on different locali- 

 ties. 



Sometimes it is simply the question of water. Along 

 the creeks (where there is usually better humus) there are 

 vine-scrubs ; further on there is open forest country. In 

 some localities a forest pocket occupies a circular slightly 

 elevated ground between rich alluvial soil timbered with 

 vine-scrub. In other places, however, the reasons are 

 insufficient to explain this sharp line. Besides the con- 

 ditions stated,, I found these factors of great importance. 

 1. The forest flora consists of true Australian types ; 

 the scrub flora for the greatest part of Malayan and Papuan 

 types. The historic evolution of these elements has been 

 quite diverse, and we find always that they never come into 

 a friendly contact. They are of quite different character, 

 and on localities where the conditions are not decidedly 

 E — EoYAL Society. 



