38 



DIVISION I. — GENERAL MORPHOLOGY. 



fissure in the rind, and formed therefore in all probability from a single branch 

 proceeding from a peripheral medullary hypha and piercing through the rind. 



The exceptional case mentioned above, in which the product of the sclerotium 

 is not a compound structure, is the formation of simple filamentous gonidiophores, 

 known by the name of Botrytis < inn-ca, from the sclerotia of Peziza Fuckeliana. In 

 most of the cases which I have myself examined a bundle of hyphae shoots out from 

 the subcortical medullary region, and where it has broken through the rind the 

 hyphae spread in different directions, and each developes into a gonidiophore. But it 

 sometimes happens that the cells of the rind develope directly into gonidiophores. 



In none of the sclerotia that have been examined is the origin of the shoots 

 connected with a definite predestined morphological spot. Any fragment of the larger 

 sclerotia, if not too small, can under ordinary circumstances produce them, as Tulasne 

 showed in the case of Claviceps, and Brefeld especially in that of Coprinus stercorarius. 



The number also of the shoots that may proceed from a sclerotium is not 

 definite in any species ; and some species can produce an almost unlimited number 



FIG. 18. a andr Claviceps purpurea, b C. microcephala.T. a and* scle- 

 rotia with mature sporophorcs. c transverse section through a sclerotium 

 with the young sporophores emerging from the interior. After Tulasne. ,i 

 and * nat. size, c slightly magnified. 



Fig. 19. Sclerotitiia Fuckeliana, a very 

 small specimen, s transverse section through 

 a sclerotium, from which a sporophore cut 

 through lengthwise has proceeded. The 

 dark spots in the sclerotium are the dead cells 

 of the vine-leaf which it has occupied ; the 

 spots and dots at / are calcium oxalate 

 aggregations. Magn. 20 times. 



of these primordia (Anlagen) of sporophores on their sclerotia, others cannot do this. 

 Vigorous specimens of Coprinus stercorarius, according to Brefeld, may produce 

 hundreds of primordia, of which however few are ever perfected, and if those already 

 formed are intentionally and repeatedly destroyed hundreds of fresh primordia as 

 repeatedly make their appearance. Oth<r species are less productive; Sclerotinia 

 Sclerotiorum seldom has two dozen sporophorcs even on strong plants; species with 

 small sclerotia have usually one only or very few. 



The size of the individual sclerotia on one and the same species, other conditions 

 being the same, generally causes a difference in the number of the sporophores 

 which commence and complete their development, and in the vigour of growth of the 

 latter. Larger sclerotia are on the whole more productive than the smaller. 

 Claviceps purpurea produ< i s 20-30 sporophorcs from such large sclerotia as are 

 formed upon the ears of Secale cereale, but only one or a i'cw weakly ones from the 

 small sclerotia upon the spikelets of Bromus, Lolium, and Anthoxanthum. Similar 

 differences arising from the size of the sclerotia are observed also in Sclerotinia 

 Sclerotiorum and in Coprinus. The relation between size and productiveness is the 



