BUREAU OF ANIMAL INDUSTRY. 



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The sphacelia, however, Is not the ergot form of t he fungus. At the base 

 of this is produced a hard substance with a black or dark violet surface, 

 and white or grayish within, which is the true ergot or sclerotiuin stage 

 of the claviceps fungus. In the earliest period of the development of 

 the sclerotiuui this is entirely covered by the sphacelia, but it gradually 

 increases in size and pushes the sphacelia before it until the latter is 

 raised entirely beyond the floral glumes, and is supported on its summit 

 (PI. VIII, Pigs. 1, ,~>, 6). The sclerotium, or ergot, continues to increase in 

 size and length, and the deformed ovary or sphacelia adheres to it for a 

 long time, and may even be found in a considerable proportion of the 

 specimens as seen in hay or mature grain after curing. In these the 

 form of the stigma can be readily made out in most cases by the use of 

 a low power lens. 



Ergot is not therefore a diseased seed ; on the contrary, it develops 

 entirely below the ovary and prevents the formation of the seed. It is 

 entirely a fungus growth, and is the resting stage of the organism. It 

 contains little or no starch, and its microscopical structure is that of the 

 sclerotic mycelia. The sclerotium is looked upon as a hard compact 

 mass of imperfectly developed mycelia. It appears to be about a month 

 from the time the fungus invades the ovary until the ergot is fully 

 formed. 



The ergot is the dormant form of the fungus, and remains in this con- 

 dition until autumn, or usually until the next spring. If at this time it 

 is in contact with the damp ground it germinates and stromata grow 

 from its surface (PI. VIII, Fig. 7). These consist of a long stalk and a 

 globular head, and become perfect fruiting fungi. In the head a large 

 number of flask-shaped perithecia are formed (see PI. VIII, Fig. 8), 

 which are filled from the bottom with a number of asci (PI. VIII, Fig. 9), 

 each of which contains several stender filiform spores (PI. VIII, Fig. 10). 



When the spores reach the young flowers of rye, red top or other 

 nearly allied grasses, they germinate and form a mycelium which 

 invades the wall of the ovary and again produces a sphacelia. With 

 this the cycle of development of the fungus is completed and we 

 probably have its entire life history. The meteorological conditions 

 most favorable for the production of ergot are not well known. It has 

 been asserted that it only appears in large quantities in rainy seasons, 

 but others believe that moisture has little or no influence on its devel- 

 opment. It is also uncertain whether more than one species of clavi- 

 ceps is concerned in the production of ergot in the different varieties of 

 grasses. The ergot of the red-top hay in Missouri and Illinois produced 

 identical effects with that in the wild rye of Kansas, and it would 

 therefore appear that the physiological effects are substantially the 

 same even though the species growing upon these two plants may be 

 different. 



The grains of ergot of rye are from half an inch to over an inch in 

 length, and from one-fifteenth to one-sixth of an inch in diameter ; they 

 are nearly cylindrical, sometimes slightly ribbed and furrowed, and often 

 have irregular fissures ; they are curved, and taper toward the ends. 

 The color of the surface varies from dark violet to blue-black or black ; 

 the interior is white, often tinted with violet. The ergot of wild rye, 

 blue grass, and red top has the same general appearance, but flic 

 grains are smaller. In red top many of the grains are so small that 

 they are only recognized with difficulty by the unaided eye. Some- 

 times the taste is pronounced and disagreeable ; but the ergot in the 

 wild rye of Kansas, where the outbreaks of disease occurred, was al- 

 most or entirely without taste, and certainly was in no sense disagreea- 

 ble when masticated. 



