lo Vegetative Organs. 



I had a very good illustration of this in the case of a barley plant affected 

 with Naked smut {Ustilago nuda). It is commonly stated that the stubble 

 of wheat and barley will not sprout again, because the original forms are 

 annual ; but under our conditions with the ripening season in the summer, 

 and not in the autumn, they may be cut back while still somewhat green and 

 shoot again, and behave as if biennial. This occurred in a plot of Battledore 

 barley sown at Burnley on 2nd July. The ears in one plant were all smutted 

 with the Naked smut, and this smutted stool was cut close to the ground on 

 6th November, before it was dead ripe, in order to encourage a new growth. 

 The season was favorable and a second growth started, and by the 24th 

 December fresh ears were formed, which were also all smutted, as in the first 

 instance. In this case when the plant was cut down, the mycelium still 

 remained alive in the basal portion, particularly in the nodes, and when 

 fresh shoots were formed later on, the mycelium entered into them and 

 produced the disease. Sections of the lowest node revealed the presence 

 of fungus filaments, so that it was not by shoot infection, but from the 

 perennial mycelium that the fungus arose. 



Not only may a cereal crop be cut once and shoot up again, but it may 

 even do so a second time. In Victoria this happened with a crop of oats. 

 The land was ploughed and sown in October, 1907, and about 10 acres were 

 sown with Algerian oats. The crop was cut in January, 1908, and yielded 

 about 25 cwt. to the acre. Then heavy rain set in and the crop was cut again 

 in April, yielding hay of splendid quality, and averaging 1 ton per acre. 

 The paddock was heavily stocked from April to October, when it was again 

 closed to stock, and the third cutting taken off in December, 1908. This 

 was the heaviest crop of all, and yielded about 30 cwt. per acre. The land 

 was open plain country, at an elevation of 3,500 feet above sea level. If 

 smut had been originally present in the crop it would probably have appeared 

 in each successive cutting. 



Although the mycelium may thus permeate the entire plant, it is only 

 at certain definite spots where spore-formation occurs. In the case of 

 Tilletia tritici, however, Berkeley^ has recorded an instance w^here a streak 

 of the smut spores appeared on the outside of the stem, thus showing that, 

 while the normal appearance of the spores is in the grain, they may be 

 produced in the stem under rare conditions. I have also observed in Ustilago 

 tritici that, while the spores are usually produced in the spikelets, they may 

 occasionally occur in elongated streaks on the sheathing blade or shot blade 

 enveloping the ear in its earliest stages, as well as on the stem (Plate VI., c) 



Localized Myceliu-ai. 



It frequently happens that where the mycelium is confined, it gives 

 ri&e to swellings known as smut-balls or smut-galls, varying from the size 

 of a pin-head to that of a child's head. These swellings in the American 

 Corn smut, for instance, are not merely due to the multiplication of the 

 fungus filaments, but also to the luxuriant growth of the tissues of the host- 

 plant. The Gall smut of Barnyard grass may give rise to elongated swellings, 

 reaching a length of 9 cm. (Plate XXI.). 



The mycelium is generally hidden in the tissues of the host-plant, but it 

 sometimes forms a fungus membrane on the outside. This only occurs, 

 however, in connexion with, and as a protective covering for. the spores 

 until they are ready for distribution. 



