FUNGI. — ASCOMYCETES. lOl 



antheridial branch was formerly called the poUinodhwi. The sexual function of 

 these two organs, the aniheridium and the archicarp, that is, a transference of fer- 

 tilising matter from the former to the latter, has not been ascertained in this genus 

 any more than in the Saprolegnieae, and it probably does not take place; it is 

 probable, that is, that the organs actually existing and homologous with those of 

 the Peronosporeae have lost their function. But the archicarp does not behave as 

 an oogonium in respect to the differentiation of its contents; that is, no oosphere is 

 formed in it, but, in consequence perhaps of a fertilising operation of the antheridium 

 on its coTitents, it developes into an ascus by the division of a part of its proto- 

 plasm into a number of round bodies, each of which becomes invested with a 

 cell-wall and forms an ascospore. Moreover, hyphae springing from beneath the 

 basal wall of the archicarp and also from the antheridial branch grow up round the 

 archicarp at an early period ; the hyphae are divided into cells by transverse walls 

 and form a compact envelope round the young ascus (compare the zygospore of 

 Moriierella, p. 90). Podosphaera is one of the Erysipheae. In other members of 

 that family the ascus-fruclification contains several asci, which grow from a multicellular 

 archicarp (Fig. 63, F, ii^ ; in this case it is a stout segmented hyphal branch, which 



Fig. 63. Enlarged diagrammatic representation of the development of the fructificati( 

 F. I'odosphaera. F Ascoholus ; iv archicarp (ascogone), m antheridial branch, c s asci, h < 

 formed of sterile branches. After de Bary and Janczewski. 



gives rise to the fertile filaments (asci) that ultimately produce the spores ; for this 

 reason the archicarp is also called an ascogotie. The archicarp and the antheridial 

 branch sometimes differ little from each other in size ; sometimes, as in Gymnoasctis, 

 they are of exactly the same size ; usually the archicarp is the larger of the two and 

 is multicellular, while the antheridium is a slender branched tube, always distinguished 

 from the archicarp by the fact that it is from the latter only that the fertile asco- 

 genous hyphal branches arise. The sterile tissue of the fructification springs 

 from the cell that bears the archicarp, and sometimes from other adjoining cells. 

 The antheridial branch either lays its whole length along the archicarp, or it touches 

 with its apex only the anterior and sometimes much elongated portion of the archi- 

 carp. It has been already said that in members of this group there is no apparent 

 and direct transference of protoplasm between the antheridial branch and the archi- 

 carp, both organs continuing closed ; and usually it is not the part of the archicarp 

 actually touched by the antheridial branch but a part nearer its base from which 

 the fertile filaments of the fructification afterwards spring ; this recalls a similar 

 fact in the formation of the fructification in the Florideae. There is still greater agree- 



