122 DISCOMYCETES [ch. 



In Tkeleboliis Zukalii the origin of the ascocarp has been observed from a 

 pair of intertwined hyphae (Ramlow, 1 9 14), 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 Sphaerotheca among the Erysiphales. In 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 Sphaerotheca the original uninucleate 

 structure is the fertilized oogonium, while in Thelebo/ns stercorals an anthe- 

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

 investigation of T/i. 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 Ascophani. 



ASCOBOLACEAE: BIBLIOGRAPHY 



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



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

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



Brit. Assoc. Southport and Cambridge. 

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



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



1906 Ram low, G. Zur Entwickelungsgeschichte von Thelebolus stercorals. Bot. Zeit. 

 lxiv, p. 85. 



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

 cetes. Le Botaniste, x, p. 304. 



1907 WELSFORD, E. J. Fertilization in Ascobolus furfuraceus. 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 Ramlow, 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 prosenchymatous, 

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

 walled. In the Mollisiaceae it is parenchymatous, of round or polygonal 

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

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



