THK STOHY UK SOME COMMON 1'LAXTS. 145 



Phormium tenux, although an indigenous plant, is not immune 

 from " pests '" of various kinds, some of which are vegetable and some 

 animal. Circular black spots formed by a microscopic fungus (Clndios- 

 l><>n' tun) cause not only tho premature death of the leaf, but also 

 render the fibre discoloured for milling purposes. Leaf-spot is a 

 worse disease still, red disc derations being formed on the surface 

 of the blade. Perhaps the worst enemy of the plant, and certainly of 

 the flax-miller, is an indigenous slug which eats out patches on the 

 under-surface of the leaf. Strange to say, according to the researches 

 of T. W. Kirk and A. H. Cockayne, " these gouged-out portions of the 

 leaves are frequently attacked by a fungus (Rhizopus nigricans), but 

 this fungus never seems to attack healthy plants." The leaf- 

 margin is the point of attack of various caterpillars, who cause jagged 

 wounds. 



