CHAPTER III. — SPORES OF FUNGI. 79 



others. The contents of the asci in most of the Pyrenomycetes which have been 

 examined show only the yellow coloration of protoplasm with iodine ; but the 

 glycogen reaction is beautifully shown in Sphaeria obducens during or even before 

 the formation of the spores, and in Pleospora herbarum, Sordaria fimiseda, and Sphaeria 

 Scirpi after their formation. All these facts tend to show that the developement of 

 the eight-spored asci in the Pyrenomycetes is essentially the same as in the Discomy- 

 cetes, and that further observations will confirm this view. 



The eight-spored asci of Podosphaera Castagnei have a large nucleus in the young 

 state ; this subsequently disappears, and the spores which are formed simultaneously 

 have very distinct central nuclei and are imbedded in a glistening glycogen-mass. 



Nuclei were found also by Fr. Schmitz in the asci and spores of Exoascus Pruni ; 

 in other respects the development of the spore is entirely the same in this species 

 as in the Discomycetes (see also section LXXVI). 



The number of primordia of spores laid down in the typically 8-spored asci is very 

 constant; exceptions are comparatively rare, such as that of 9 spores in Cryptospora,Tul. 

 and in Exoascus, and 13 developed normally in a single ascus of Peziza melaena. It 

 more frequently happens, especially in the Pyrenomycetes and Lichen-fungi and accord- 

 ing to Boudier in Ascobolus also, that some of the 8 spore-primordia remain unde- 

 veloped ; most of the cases in which less than 8 spores have been found in species 

 in which that is the typical number, may probably be thus explained. The abortion 

 of individual spores is almost always an accidental phenomenon ; it occurs regularly, 

 according to Tulasne's account 1 , only in Collema cheileum, where the mature ascus 

 always (?) contains aborted as well as perfect spores, the aborted ones adhering irregu- 

 larly to one another or to the perfect spores. 



A larger or smaller number than 8 is the typical number of spores in the asci 

 of some Ascomycetes ; 1-2 for example in Umbilicaria and Megalospora, Mass. ; 2 in 

 Erysiphe guttata, Pertusaria sp. and Endocarpon pusillum ; 4 in Erysiphe sp. and 

 in Aglaospora profusa; 16 in Ascobolus sexdecimsporus, Crouan 2 , Hypocrea rufa, 

 P., H. gelatinosa, Tode, H. citrina, Tode, H. lenta, Tode, &c. 3 ; 40, 50 and more in 

 Diatrype quercina and D. verrucaeformis, Calosphaeria verrucosa, Tul., Tympanis 

 conspersa, Fr., and T. saligna, Tode ; the genera Bactrospora, Acarospora, and Sar- 

 cogyne of Massalongo have over 100 spores, most species of the genus Sordaria 4 

 have 8-spored asci, but in some the asci have 4, or 16-64, or even 128 spores. In 

 some species again the number varies ; the asci of Dothidea Sambuci, Fr. produce 

 2-4 spores, those of Erysiphe sp. and Pertusaria sp. 4-6, Sordaria fimiseda 4-8, S. 

 pleiospora 16-64, and others might be mentioned; in Tuber the number of spores 

 varies as much as from 1-6, and in Elaphomyces from 1-8. The history of the 

 development of these asci has not been so accurately studied, if we except the asci of 

 the two last genera, as that of the typically 8-spored asci ; still all that is known of 

 it and of the spores themselves, especially their simultaneous appearance, agrees with 

 the account which has been given of the 8-spored genera. The genera nearest allied 

 to these often have asci with 8 spores, Erysiphe for example, Diatrype, Aglaospora 

 and Calosphaeria ; and asci with 4 as well as 8 spores occur in some species of 

 Sordaria and in Valsa ambiens, V. salicina and V. nivea, some in the same, some 

 in separate perithecia. Hence it may very well be presumed that the formation 



1 Mem. sur les Lichens. See the literature cited at close of section LXXIV. 



2 Crouan in Ann. d. sc. nat. ser. 4 (1858). 



3 See Currey in Trans. Linn. Soc. London, XXII. 



1 G. Winter, Die deutschen Soidarien, Halle, 1873. 



