290 



BOTASTT. 



so on. The contact of an infected head of rye with an unin- 

 fected one is sufficient to communicate the fungus to the 

 latter, and doubtless the conidia are also freely carried by the 

 winds, and, to a certain extent, by insects. It appears that, 



in some cases at least, 

 the germinating co- 

 nidia produce, fii"st, 

 short hyphfe, which 

 bear a few small 

 spores {sporiclia, D, 

 Fig. 198, x), which 

 themselves g e r m i - 

 nate, and then pro- 

 duce the sphacelia ; it 

 is doubtful, however, 

 whether this always 

 takes place. 



384. — After the 

 conidial stage, the 

 mycelium at the base 

 of the ovary becomes 

 greatly increased, and 

 assumes a hard and 

 compact form ; it 

 grows with a consider- 

 able rapidity, and car- 

 ries up on its summit 

 the old sphacelia and 

 the remains of the 

 ovary 



Pig. l9S.—Clai!lceps jnirpurea. A, young sclero- 

 tinm, c, with old ephacelia, s ; p, the apex of the dead _. .„, j „„<.„„,,„ j 

 ovary of rye. B, upper part of J., in longitudinal sec- "OW-aeSIl OyCU 

 tion, showing epiiacelia, 8. C, transverse section / 4 anA R Vier 1 Qe\ 

 through the sphacelia more highly magnified; m, the \^^ <iiiu. i>, rjg. ±^0). 

 mycefium, surrounded with the hypha; b, heai 

 nidia 



hypha; 6, bearingco- T'Kp 



horn- 



; p. conidia fallen off ; w, thVwall of the ovary. -^ " ^ COmpaCt, 

 i>, germinating conidia, forming sporidia, a. A and ghanpd and dark-onl- 

 B moderately, and S highly magnifled.-After """^P*^"' ■*""■ "'^"<- ^^l 



Sachs. ored body which re- 



sults is called the sclerotium ; that which is produced upon 

 rye is from one to three centimetres long (.4 to 1.2 in.) and 

 from two to six millimetres in diameter (.08 to .25 in.) ; on 

 other grasses it is usually of less size. The sclerotium occu- 

 pies the position of the displaced ovary, and in the autumn 



