Review. 
ri7 
PROFESSOR BOWER ON THE THEORY OF ANTITHETIC 
ALTERNATION OF GENERATIONS. 1 
RITISH plant-morphologists, especially those who interest 
themselves in that striking phenomenon which characterises 
the life-histories of a great portion of the vegetable kingdom, the 
regular alternation of sexual and asexual generations, have been 
expecting the publication of the present work with great interest. 
Pi'ofessor Bower’s name, perhaps more than that of any other 
botanist, is identified with research into the morphological problems 
connected with this great and still incompletely understood pheno¬ 
menon of plant-life. It is to him, more than to any other, that we 
owe the great revival of interest in these problems which took place 
in this country about twenty years ago; it is to him that we owe 
the stately series of memoirs embodying a very large portion of 
our detailed knowledge of the structure and development of the 
“ spore-producing members ” of the Pteridophytes, investigations 
undertaken with a view to elucidating certain aspects of the general 
problem ; and it is very largely to the stimulus of his enthusiastic 
example that we owe the general accumulation of researches— 
largely British—on the structure and development of the Arche- 
goniatte which have made this group to-day one of the most 
completely investigated in the plant-kingdom. 
The debt that morphologists owe to Professor Bower is there¬ 
fore no inconsiderable one, and the publication of his matured 
conclusions—the results of the thought and research of half a life¬ 
time—is naturally an occasion that calls forth our gratitude no less 
than our interest. 
The main thesis of the book before us is the same which the 
author put forward nearly eighteen years ago in a paper “ On 
antithetic as distinct from homologous alternation of generations,” 
published in the fourth volume of the Annals of Botany. In that 
paper, as Professor Bower says in the preface to the present work, 
“ the main position of Celakovsky in discriminating between 
Homologous and Antithetic Alternation was adopted ; but the latter 
type, as seen in Archegoniate Plants, was recognised as having been 
fixed and perpetuated in accordance with the adaptation of aquatic 
organisms to a Land Habit.” The essence of this theory is that 
not only the sporogonium or fruit-body of the Bryophytes, but also 
the sporophyte or leafy plant of the Pteridophytes has arisen as a 
new intercalated phase in the life-history of a hypothetical gameto- 
phytic ancestor which did not possess such a phase, by gradual 
elaboration of the oospore or fertilised egg. 
Recognising that the morphological and developmental facts 
were at that time much too inadequately known to allow of a full 
and reasoned statement of this theory, Professor Bower undertook 
the series of “ Studies in the morphology of spore-producing 
members ” to which we have already alluded, and on the completion 
of these in 1903 at length found himself in a position to put forward 
1 The Origin of a Land Flora, a Theory based upon the facts of 
Alternation, by F. O. Bower, Sc.D., F.R.S., Regius Professor 
of Botany in the University of Glasgow. Pp. XII. and 727. 
361 Figures in the Text. London, Macmillan & Co., 1908. 
Price 18/- net. 
