MORPHOLOGY OF THE ASCOCARP. 2g 



Dangeard persists in professing himself quite indifferent to the 

 existence of antheridia and oogonia as the initial cells of the ascocarp, 

 if only they be not functional at the present time ; but one can hardly 

 believe him so lacking in penetration as not to realize that so long as 

 the Ascomycetes are regarded as a monophyletic group the establish- 

 ment of the existence of antheridia and oogonia as the initial cells of 

 the ascocarp settles at once, and finally, the old question of the sex- 

 uality of the group in favor of the views of De Bary and his school 

 and against those of Brefeld — and this, too, without any regard to the 

 question as to whether these sex cells are functional or not. Interesting 

 evidence on this point is shown in the attitude of the present adherents 

 of the views of Brefeld (57), who are solely interested in the question 

 whether archicarps, pollinodia, etc., are really sexual cells, and appear 

 relatively indifferent as to the existence of the fusions in the asci. No 

 one can reasonably doubt that the antheridia of the Saprolegniaceae are 

 sexual germ-cells, regardless of the question as to whether they are 

 functional at the present time. The proof brought by Trow (95) that 

 a fusion of cells and nuclei occurs at the present time is confirmatory 

 evidence of their sexual nature, but it is in no way necessary for their 

 correct morphological characterization as compared with corresponding 

 structures in other groups of algaa and fungi. It was the supposed 

 similarity of De Bary's antheridial branch in the mildews to the later- 

 developed perithecial branches which was a justification for doubt as 

 to its morphological nature and made it necessary to show that it was 

 a functional male branch in order to establish its morphological char- 

 acter. Could De Bary have brought such evidence of the special differ- 

 entiation of its walls and its fate in the developing perithecium as can 

 be found by modern methods in Phyllactinia, in addition to the facts as 

 to its origin, position, etc., we can hardly imagine that its sexual nature 

 would ever have been doubted, regardless of whether it was shown to 

 be functional at the present time. The ascus is in its origin a new 

 structure, the outgrowth of ascogenous hyphse and ascogonium, and 

 the fusion of nuclei which occurs in it, whatever may be its physiological 

 nature, is not homologous with the fertilization of the egg out of which 

 the ascogonium develops. It is thus fairly established and admitted 

 that the " macrocysts and paracysts " of Pyronema and the " archicarp 

 and pollinodium " of the Erysipheae and other Ascomycetes are to be 

 compared morphologically to the gametangia and oogonia and anther- 

 idia of other fungi and algae, and that the ascogonium, ascogenous 

 hyphse, and asci are new structures gradually developed in the evolu- 

 tion of reproductive processes, just as are the gonimoblasts and carpo- 

 spores of the red algae. 



