122 



DISCOMYCETES [CH. 



In Thelcbolns Znkalii the origin of the ascocarp has been observed from a 

 pair of intertwined hyphae (Ramlovv, 1914), but the cytology and further 

 development have not yet been described. 



The closest analogy to the development of the ascocarp in Thelebolus is 

 perhaps to be found in SphaerotJieca among the Erysiphales. I n both we have 

 a hypha which is at first uninucleate, later multinucleate. In both it divides 

 to form a row of cells most of which enclose one nucleus. In both a single 

 binucleate cell, typically penultimate, gives rise to the single ascus in which 

 nuclear fusion takes place. But in SpliaerotJieca the original uninucleate 

 structure is the fertilized oogonium, while in Thelebolus stercoreus an anthe- 

 ridium has not been demonstrated. It remains to be seen what light the 

 investigation of Tli. Zukalii will throw on these homologies. In view of 

 the direct transformation of one cell of the row into an ascus, it becomes 

 unjustifiable to correlate the septate structure here with the young archicarp 

 of the Ascoboli or AscopJiani. 



ASCOBOLACEAE: BIBLIOGRAPHY 



1896 HARPER, R. A. Ueber das Verhalten der Kerne bei der Fruchtentwickelung einiger 



Ascomyceten. Jahr. fiir wiss. Bot. xxix, p. 655 

 1903, 4 BARKER, P. T. B. The Development of the Ascocarp in Rhyparobius. Kept. 



Brit. Assoc. Southport and Cambridge. 

 1906 OVERTOX, J. B. The Morphology of the Ascocarp and Spore-formation in the many 



spored Ascus of Thecotheus Pelletieri. Bot. Gaz. Ixii, p. 450. 



1906 RAM LOW, G. Zur Entwickelungsgeschichte von Thelebolus stercoreus. Bot. Zeit. 

 Ixiv, p. 85. 



1907 DANGEAKD, P. Recherches sur le developpement du perithece chez les Ascomy- 

 cetes. Le Botaniste, x, p. 304. 



1907 WELSKORD, E. J. Fertilization in A scobolus frtrfuraceus. New Phyt. vi, p. 156. 

 1909 CUTTING, E. M. On the Sexuality and Development of the Ascocarp in Ascophanus 



carneus. Ann. Bot. xxiii, p. 399. 

 1909 FRASER, H. C. I. and BROOKS, W. E. St J. Furthur Studies on the Cytology of 



the Ascus. Ann Bot. xxiii, p. 537. 

 1912 DODGE, B. O. Methods of Culture and the Morphology of the Archicarp in certain 



Species of the Ascobolaceae. Bull. Torrey Bot. Club, xxx, p. 139. 

 1914 RAM LOW, G. Beitrage zur Entwickelungsgeschichte der Ascoboleen Myc Cen- 



tralbl. v, p. 177. 



Helotiaceae and Mollisiaceae 



The Helotiaceae and Mollisiaceae are distinguished from the Pezizaceae 



by the fact that their peridium differs more or less definitely in structure 



from the hypothecium. In Helotiaceae the peridium is prosenchvrhatous 



>mposed of elongated parallel hyphae, usually light in colour and thin- 



ed. In the Molhs.aceae it is parenchymatous, of round or polygonal 



cells usually thick-walled and dark-coloured. In both families the ascus 



! ejection of a plug, and not, as in most Discomycetes, by a lid. 



