BLACK RUST 247 



be repeated. There is also a danger of infection by spores 

 produced by the crop ; a condition accepted by Eriksson, 

 if only to a limited extent, 



The following literature may be consulted as bearing on 

 the subject : 



De Bary, Mon.-Ber. der -Akad. der Wiss. zu Berlin, Sitz. 

 1 2th Jan. 1865. 



Cobb, Agric. Gaz. N.S. Wales, vol. i. No. 3 ; vol. iv. 

 No. 6. 



Eriksson and Henning, Die Getreideroste, 1896. 



Marshall Ward, Ann. Bot., vol. ii. No. 6, 1888. 



M' Alpine, Dept. Agric. Victoria, Bull. 14, 1891. 



Farrer, Dept. Agric. N.S. Wales, No. 206 (1898). 



BLACK RUST 



(Puccima graminis, Pers.) 



This universally distributed species is the one most 

 injurious to cultivated cereals, attacking wheat, oats, barley, 

 and rye, but is most general on wheat. It is also common 

 on numerous wild grasses, occurring on one hundred 

 different species in Sweden alone, according to Eriksson. 



The aecidia occur in clusters seated on orange spots on 

 living leaves, young shoots, flowers, and fruit of various 

 species of barberry Berberis and the allied genus 

 Mahonia. The uredo and teleuto spore conditions form 

 small streaks on the leaf-sheath, leaf, culm, and less fre- 

 quently on the chaff of grasses. The uredo streaks are 

 rusty orange the teleutospore streaks, which appear later 

 in the season, blackish. An account of the life-cycle of 

 this species is to be found at p. IT. 



