Letters on the Diseases of Plants. 



15 



On the other hand the wheat-rust does sometimes attack various grasses, 

 but unfortunately I have been obliged to answer inquiries on this subject 

 for the most part somewhat as follows : — " It is difficult to recommend any 



Fig. 14.— Section through part of a 

 flax-rust pustule, showiug' on the 

 left the marginal iDeridium of the 

 pustule. X 175. 



Fig. 15. — Face view of 

 the peridiiuu shown in 

 Fig. 14. The wider 

 black lines are to show 

 the epidermal cells of 

 the flax. 



Fig. 16.— Teleutospore! 

 of the flax-rust. x325. 



measures against rust on pasture grass. I do not remember to have seen any 

 recommendations on the subject that appeared to be of much value, and my 

 own investigations have led (so far as pastures are concerned) to no practical 

 remedies. Remedies there are, such as spraying with copperas, &c., but the 

 necessary machines are not to be procured in the Colony, and the process is 

 too expensive in any case. No doubt burning off the grass would do some- 

 thing towards lessening the loss, but to be effective the burning would have 



^^^=^:::^^ 



Fig. 17.— Teleutospores of the flax- 

 rust, differing somewhat in form 

 from those shown in Fig. 16. x 325. 



Fig. 18.— Uredospore of the flax-nist, germinating. 



to be simultaneous by owners over a large area. Some grasses are much 

 less liable to rust than others, but unfortunately the best grasses for the 

 South Coast districts are the very ones that are most liable to rust. I refer 

 to rye-grass and the various species of Poa." 



5. Smuts and Bunt. 



Probably no diseases bring me more inquiries from growers of wheat and 

 maize than do smuts. In spite of the fact that the subject of smuts is 

 easy of mastery there is a great deal of ignorance and misapprehension con- 

 cerning it. I wish the whole community could adopt more precise language 

 in speaking and writing on this question. To this end I wish to explain that 

 our wheats are subject to three diseases of this kind — 



1. Loose smut, which turns the whole ear to a black mass. 



2. Bunt, which does not much disturb the form of the ear, but converts 



each grain into a small ball filled with a stinking black powder. 



3. Mag-smut, which breaks out on the flags principally. 



This latter is disregarded in these pages, because it is uncommon in this 

 Colony. 



