Plant Defences 1 1 3 



faces, and so are prevented from cooling too rapidly. It is the 



FIG. 99. -Seedlings of Black Wattles (Acacia melanoxylon, R. Br.). 



FIG. TOO. Branch of Acacia melanoxylon, R. Br., showing phyllodes (a, b). 

 (From Thom6 and Bennett's " Structural and Physiological Botany ".) 



position of the upper leaves which gives such a delicate tracery 

 against the sky. 



