354 



On the Sexuality and Development of the Ascocarp oj 

 Humaria granulata Quel. 



By Vernon H. Blackman, M.A., Assistant, Department of Botany, British 

 Museum ; Late Fellow of St. John's College, Cambridge ; and Helen 

 C. I. Fkasee, B.Sc., Assistant Lecturer, Boyal Holloway College. 



(Communicated by Professor Marshall Ward, F.R.S. Received October 31, — Read 



December 14, 1905.) 



[Plates 13—15.] 



The observations of Harper (15, 16, 17) on Sphcerotheca, Erysiphe and 

 Pyronema, have clearly shown that some at least of the Ascomycetes exhibit 

 an ordinary sexual process. It is true that attempts have been made by 

 Dangeard(lO) to refute Harper's observations, and doubt has been cast on 

 his work by Lindau (22), Holtermann (IS), and others ; but the recent very 

 convincing work of Claussen (8a) on Boudiera* together with the strong 

 circumstantial evidence obtained by Barker (1 and 2) in Monascus and 

 Ryparobius, by Miss Dale (9) in Gymnoascus, and by Baur(3, 4), and 

 Darbishire(lOA) in lichens, and, also, the confirmation by ourselves (7) of 

 Harper's work on Sphcerotheca, leave no doubt that the sexuality of the 

 Ascomycetes is founded on a firm basis. 



The earlier non-cytological observations of a number of forms, however, 

 have shown clearly that the existence of a normal sexual process can hardly 

 be expected in all the Ascomycetes. For example, in Melanospora parasitica 

 Kihlmann (20) observed the development of the archicarp into the 

 perithecium without the intervention of an antheridium ; in Chaitomium, 

 Oltmanns (24) found that the antheridium was usually absent; in Ascobolus, 

 the earlier observations of Woronin (25) and Janczewski (10), and the later- 

 observations of Harper (16), brought to light no definite antheridium. 

 Again, among the lichens, according to the observations of Funfstuck (13), 

 in Peltigera and Peltidea the ascogonia are without trichogynes ; and Solorina 

 saccata, according to Baur's (4) researches, seems clearly to develop without 

 any ordinary fertilisation. It is obviously, then, very desirable that the 

 cytology of some member of the Ascomycetes, the ascocarp of which 

 develops without fertilisation by an antheridium, should be carefully 

 investigated. The form here studied is of this type and hence is of peculiar 

 interest. 



Humaria granulata Quel (= Peziza granulata Bull), a common Dis- 



* The form investigated by Claussen would seem to be more correctly placed in the 

 genus Ascodesmis {vide Fr. Cavara, ' Aunales Mycologici,' vol. 3, 1905, p. 363). 



