No. 464.] STUDIES ON PLANT CELL. VII. 563 



were investigated and no developments from the carpogonia 

 were found, but the cystocarp in all cases arose from a cell near 

 the base of the group of procarps. These conditions together 

 with the rarity of male plants on the American coasts (none 

 have ever been reported) give strong evidence for apogamy in 

 Ptilota. There are a number of genera of the Rhodophyceae 

 where similar conditions seem to obtain and which lead one to 

 suspect that apogamy may not be very exceptional. However, 

 the subject has been very little studied. 



As is well known, the Ascomycetes furnish numbers of illus- 

 trations where ascogonia have not been found or appear in what 

 seem to be reduced conditions and even when accompanied by 

 so called antheridial filaments these latter have not been estab- 

 lished as functional. De Bary recognized the possibility of 

 apogamy in the development of the ascocarps of these forms 

 and very little critical study has been given to them since his 

 time. The trend of investigations in this group has been 

 towards the more interesting problems of the establishment of 

 sexuality in a few well known forms (e. g., Gymnoascus, Sphae- 

 rotheca, Pyronema, Monoascus, and among the lichens and 

 Laboul beniaceae . ) 



It is generally believed that no sexual organs are present in 

 the higher Basidiomycetes (Autobasidiomycetes). But the 

 recent studies of Blackman' (: O4a) in the Uredinales, taken in 

 relation to the well known nuclear fusions in the basidium, pre- 

 ceded by a mycelium containing paired (conjugate) nuclei, make 

 it seem very probable that former sexual processes in the Basi- 

 diomycetes have been replaced by a remarkable type of apog- 

 amous development of a sporophyte generation. Blackman has 

 traced the origin of the paired nuclei in the Uredinales (Phrag- 

 miclium) to a structure preceding the aecidium, a structure. which 

 seems to be the remains of a female sexual organ. We will 

 take up this investigation presently. There is then much 

 reason for believing that a sporophyte generation in the Basi- 

 diomycetes arises apogamously in the creation of the paired 

 nuclei and terminates with their fusion within the teleutospore 

 or basidium. 



The leptosporangiate ferns have furnished some of the best 



