QUEENSLAND RAIN FORESTS AND TREES. 213 



BUTTRESSED BARRELS. 



]\Iany I'aiu-forest trees are deeply Hanged or buttressed 

 (l)lank-bnttressed) at the base of the barrel, a peculiarity 

 which appears to be exhibited by certain species of trees in 

 dense rain forests in tropical and subtropical parts of the 

 world. J. H. Maiden'' has recorded the buttressed character 

 of several common Australian rain-forest trees. A. F. W. 

 Schimper" remarks that the plank-buttress is a peculiarity 

 of trees in a tropical climate with abundant rainfall, that 

 the amount of rainfall necessary for its appearance is not 

 yet ascertained, and that the physiological causes of the 

 phenomenon and its significance to the life of the tree are 

 still obscure. As plank-buttresses are common in all of the 

 luxuriant rain forests mentioned previously in this paper, 

 even in those at an altitude of 3,500 feet in latitude 28-2 

 degrees south, on the MacPherson Range, it can be definitely 

 stated that in Queensland the phenomenon is not confined to 

 trDjiical forests, but occurs in relatively temperate climates, 

 and tluit it appears when the annual rainfall approximates 

 or exceeds 60 inches. 



A large number of species of Queensland rain-forest 

 trees have i)lank-buttresses. Following are. the most con- 

 si)icuous trees which exhibit this peculiarity: — Fig trees 

 {J''icHs spp.), the carribin [Sloanea WooJIsii), blueberry 

 ash { Ehvocarpus ohovaius), quandong {Elaocarpus 

 (jrandis), mountain beech {Ehrocarpiis Kirfo)ni), Di/soxy- 

 lon spp., booyong {Tarrictia argyroch ndron) and its 

 varieties, black jack {Tarrictia actinophuUa), water gum 

 {Eugenia Francisii), Eugoiia Luchrnanni, Eugenia spp., 

 red cedar {Cedrela toona, var. austral is), marara {Wein- 

 ntannia laclniocarpa) , pink marara {Gcissois Bcntham-i), 

 and the giant irouwood {Syncarpia suhargcntea) . The 

 buttresses of some species often assume characteristic 

 shapes. For example, the carribin {Sloanea WooUsii), 

 wliic-h is one of the most conspicuously buttressed trees, 

 frequently has fianges whose edges curve outwards. 



"J. II. Maiden, •' Australian Vegetation," Federal Handbook on 

 Australia, issued in connection with visit of British Assn., 3914, p. 172. 



"A. F. W. Schiinper, "Plant Geography," trans. W. E. Fisher, 

 revised and edited. Groom and Balfour, p. 305 (1903). 



R.s. — p. 



