ERGOT (CLAVICEPS) 



241 



the last is the case in the Truffles (Tuber), whose fruit-bodies 

 are, moreover, subterranean. 



Ergot (Claviceps) infests the ovaries of Rye, Oats, and other 

 Grasses, becoming very conspicuous at the time of harvest, as 

 a result of the gradual replacement of the grains by a black 

 banana-shaped mass (about half an inch long) of closely inter- 



FIG. 128. Ergot of Rye (Claviceps purpurea). A, Head of Rye, with a 

 number of black sclerotia (s.). B, Longitudinal section of gynaecium 

 of Rye-flower, showing the dense hyphae forming the sclerotium in 

 the lower part, and the looser mass of hyphae producing gonidia in 

 the upper. C, A small part of the latter in section, highly magnified, 

 showing the budding off of gonidia. D, Germinating sclerotium. 

 E, Vertical section through one of the swellings arising from the 

 latter, showing numerous perithecia (p.). F, Part of same, highly 

 magnified, to show perithecia with asci (a.). G, Three asci and (on 

 the right) four of the thread-like ascospores. (A and D after Wett- 

 stein ; the remainder after Tulasne.) 



woven hyphae (Fig. 128, A, s.). This constitutes a resting-stage 

 of the Fungus, and is so hard that the term sclerotium 1 is applied 

 to it. In transverse section all the hyphse, and especially those 

 at the periphery, are seen to have very thick walls, whilst the 



1 Similar sclerotia occur, as resting-stages, in the life-cycle of several 

 other Ascomycetes, e.g. Sclerotinia (Fig. 126, E), a close ally of Peziza, 

 whose cup-shaped apothecia arise from the sclerotia. 



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