MYCOLOGIA 



Vol. XII 



May, 1920 



No. 3 



THE LIFE HISTORY OF ASCOBOLUS 



MAGNIFICUS -rfJSSSS r,-r r - 



ORIGIN OF THE ASCOCARP FROM TWO S\tU^NS Qor 



B. 0. Dodge 



(With Plates 7, 8, and Figures 1-28 in the Text) 



During the years since Ascobolus magnificus was first de- 

 scribed (6), I have been carrying on from time to time culture 

 studies of this fungus with the hope of being able to settle sev- 

 eral puzzling questions that have arisen with regard to it. Ap- 

 parently it has been collected in Porto Rico several times and 

 some of these specimens have been identified by Dr. F. J. Seaver 

 and deposited in the herbarium of the New York Botanical Gar- 

 den. The identification of the forms from Porto Rico could be 

 checked up by the use of artificial cultures. It is certainly un- 

 known in Europe or otherwise except from my cultures. In this 

 preliminary paper I shall discuss briefly the f ollowing topics : ( 1 ) 

 The development of the primordia — ascogonia and antheridia. 

 (2) The asexual or Papulospora stage. (3) Intrahyphal myce- 

 lium. (4) The necessity of two strains in sexual reproduction. 



Atkinson ( 1 ) , in his usual vigorous style, arrayed the evidence 

 against a theory of the origin of the Ascomycetes from the Flori- 

 deae and endeavored to show how the Oomycetes, through Dipo- 

 dascus, may have been the ancestors of our " higher " Ascomy- 

 cetes. It was his opinion that the trichogyne could have arisen 

 by the further development of the receptive papilla of the oogo- 

 nium. He says that no one has ever proved that the multi- 



[Mycologia for March (12: 59-114) was issued April 8, 1920] 



115 



