766 Blackman and Welsford . — The Development of the 
P. rubrum is to be added to the already long list of Ascomycetes in 
which the normal sexual process is absent. It is, however, to be dis- 
tinguished from the majority of such forms by the fact that well-marked 
male and female reproductive organs are produced, but both are abortive. It 
resembles Gnomonia erythrostoma in this respect, but the ascogonia are much 
more clearly marked than in that form. It is probable that Xylaria is 
similar to Polystigma , for in that form according to Fisch the ascogonia de- 
generate later. In Pot^onia^ Miss Dawson (4) finds at the base of the young 
perithecium ‘ a group of stouter deeply-stained hyphae, presumably the re- 
mains of the coil, and now representing the young ascogenous hyphae \ It is 
clear from this quotation that a reinvestigation of Poronia might show that 
the ascogenous hyphae really arise independently of the ascogonia, as in 
Poly stigma. In Claviceps , which requires, however, further investigation, 
there are no ascogonia, according to Fisch (5). 
The evidence to be drawn from a study of Polystigma , though not very 
strong, gives no support to the contention of Claussen (2) that there is only 
one nuclear fusion in the Ascomycetes, that in the ascus. 
The expenses of this investigation were mainly defrayed by grants from 
the Government Grant Committee of the Royal Society. 
List of Papers. 
1. Brooks, F. T. : The Development of Gnomonia erythrostoma , Pers. Annals of Botany, 
vol. xxiv, 1910, p. 585. 
2. Claussen, P. : Zur Entwicklungsgeschichte der Ascomyceten, Pyronema confluens . Zeitsch. f. 
Botanik, 4. Jahrg., 1912, p. 1. 
3. Dangeard, P. : Sur le developpement du perithece chez les Ascomycetes. LeBotaniste, vol. x, 
1907, p. 1. 
4. Dawson, M. : On the Biology of Poronia punctata. Annals of Botany, vol. xiv, 1900, p. 245. 
5. Fisch, C. : Beitrage zur Entwickelungsgeschichte einiger Ascomyceten. Bot. Zeit., Jahrg. 40, 
1882, p. 850. 
6. Frank, B. : Ueber einige neue oder weniger bekannte Pflanzenkrankheiten. Ber. d. deutsch. bot. 
Ges., Bd. i, 1883, p. 58. 
7. Fraser, PI. C. J., and Chambers, H. S. : The Morphology of Aspergillus herbariorum. Ann. 
Mycologici, vol. v, 1907, p. 419. 
