FUNGALES. 



677 



By the occurrence and growth of this fungus upon, or within the germs of 

 the grasses, a diseased condition is induced, involving the whole embryo and 

 albumen, which, when taking place on the Rye, is termed Ergot, or spur. 

 This white dust is capable of producing the same disease on any of the grami- 

 naceous plants, when placed in contact with their seeds, or even when sprin- 

 kled on the soil in which they are planted. 



If a diseased grain be examined under the microscope, when about half- 

 grown, the fungus will be seen just above the paleas, of a purplish-black co- 

 lour; at this period, some of its white coating has disappeared, and the spo- 

 ridia and filaments are no longer produced. At the upper part of the grain, 

 the coating presents an undulated, vermiform appearance, which LeveUlee 

 thought was the true fungus, and named Sphacelia segetum ; but which Mr. 

 Quekett states are merely masses of sporidia. 



Fig. 329. 



A. Side view of a longitudinal section of an infected grain, soon after fecundation. B. Front view of a 

 section of same grain, divided at a. C. Do. cut at b. D. An unripe, but advanced grain, showing at 

 the upper part, the vermiform tuberculated portion. E. Section of the same. F. Full-grown Ergot, 

 in its envelopes. 



Almost every species of the Graminaceae are liable to the attacks of this 

 fungus, and it also extends its ravages to the Cyperacese, and even to the 

 Palmacese. The Indian Corn is peculiarly subject to it, and the Ergot it pro- 

 duces is fully as powerful in its influence on the system as that furnished 

 by the Rye. 



Ergot when mature projects considerably beyond the envelopes of the grain, 

 and varies much as to numbers, in different heads; in some being solitary, 

 whilst, in others, it wholly occupies the spike. When gathered for use it 

 appears to be a solid, brittle, yet somewhat flexible grain, varying in length 

 from a few lines to an inch and a half, and in breadth from half a line to 

 four lines. Its form is cylindrical or somewhat prismatical, tapering to- 

 wards the extremities, curved like the spur of a cock, unequally furrowed, 

 on one or two sides, sometimes irregularly cracked and fissured. It is of a 

 purplish-colour externally, and of a yellowish or grayish-white within. The 



