46 CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 



may be understood from the following table, whi<3b is taken principally 

 from the classification ijroposed by Sachs : 



1 Group. Clasi'. Order. Family. Geni» 



^ I'Protoph.vta. ("G.vmnoascu.s. 



■H ^ I Z.VB<i.«|)<)rp:n. ■ | Discoinycetes. fClaviceps. 



t ^l'llXT'''^ r""''""t^: „ 5 Containing rhIoropl..vl!. ( A.sconiycete.-. J Ersiphe.^. I Cordycep.. 



I .nasi men . i c a.pu.poreic. J vvulmut flilorophvll. \ Ae.-idioniycetes. j Juberacex. Byssothecmm. 



"l Vascular Cryptoeanis. f Basidiomycete" I Pyrenomycetes. ^ FuuiHeo. 



^ ^ Phanerogam.^. ' I Lichens. I Pleospora. 



I Sphaerella. 

 iLaboiilbenia. 



The growth of the claviceps begins by the germination of conidia or 

 spores of this fungus, which have been carried by currents of air or other 

 means to the tlowersof the grasses favorable for its development. These 

 conidia or spores, as the case maj' be, germinate in contact with the ex- 

 ternal surface of the ovary while this is still in an early stage of its 

 growth, and form a mycelium which penetrates the walls of the ovary, 

 and, as a rule, respects only the summit. It thus by degrees substitutes 

 itself in place of the tissue of the ovary, and, consequently, preserves to 

 a considerable extent the form of this organ. It bears on its summit 

 the stigma, while its external coat is traversed by deep grooves and 

 irregular cavities. (In Plate VIIF, Fig. 1, is seen the normal ovary of 

 the rye plant; Fig. 2 shows the same invaded by the claviceps.) 



In this stage of its existence it has been called the sphacelia. As it 

 develops it takes entire possession of the ovary, obliterating its cavity, 

 and preventing the development of the ovule. Tlie ovule may be either 

 entirely absent or it may be present in an imi)erfect form, but does not 

 develop into a seed. The mycelium ])roduces at the surface of the ovary 

 a large number of oval corpuscles, which are called conidia, and which 

 falling upon otlier flowers may germinate and again produce the my- 

 celium or sphacelia form of the fungus. (PI. VIII, Fig. 3, which is a 

 cross-section of the ovary, now called sphacelia, shows these conidia- 

 at its borders.) 



Thesphacelia, however, isnot theergotform of the fungus. At the base 

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

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

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

 the sclerotium this is entirely covered l\y 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, Figs. 4, 5, 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 i)roportion of tlie 

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

 form (;f 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 i& 

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



