No. 463.] STUDIES ON PLANT CELL— VI. 473 
The speculative possibilities of a suppression of a sexual gen- 
eration and the assumption of sexuality by an asexual phase 
were clearly in the mind of Strasburger when he suggested 
('94b, p. 852) the possibility that the two mitoses characteristic 
of oógenesis and spermatogenesis in animals might signify the 
remains of a former sexual generation now entirely suppressed 
in the Metazoa. This suggestion was based on the striking 
similarity of the events of sporogenesis in plants to those of 
gametogenesis in animals and on the history of sporogenesis as 
shown in plant phylogeny. This history is remarkably clear and 
there can be no question but that the phenomena of sporogenesis 
have developed as the result of sexual processes and are always 
associated with an asexual generation (sporophyte). It is also 
clear that the ancestral primitive sexual generation (gametophyte) 
has steadily degenerated until now it is almost lost in such 
embryo-sacs as include the two mitoses of sporogenesis within 
their history. If the sexual generation should become entirely 
lost the life history of a higher plant would present the same 
features with respect to the period of chromosome reduction as 
that of an animal: there would be but one organism, the homo- 
logue of the sporophyte which would produce gamete nuclei with 
reduction phenomena previous to gametogenesis just as in ani- 
mals. Several authors have expressed views similar to Stras- 
burger's suggestion ('94b, p. 852) or carried the speculation even 
farther than he. Beard ('95a, p. 444) along these lines of argu- 
ment combined with conclusions from Bower's (87) studies on 
apospory, announced a belief that “ Metazoan development s 
really bound up with an antithetic alternation of generations, 
Lotsy (:05, p. 117) expresses unequivocally the view that the 
animal body represents an asexual phase (2x generation) and that 
the sexual phase (x generation) is confined to the sexual cells. 
Chamberlain (:05) simultaneously with Lotsy and in much 
greater detail presents a comparison of the phenomena of sporo- 
genesis in plants with gametogenesis in animals tracing the 
resemblance in the events of chromosome reduction step by step 
and states his belief that “animals exhibit an alternation of gen- 
eration comparable with the alternation so well known in plants. 
This is not the place to consider this theory in detail from a 
