VOLUME XXXVII NUMBER 5 
BOTANICAL* GAZEFIE 
MAY, 1904 
THE EVOLUTION OF MONOCOTYLEDONS. 
ETHEL SARGANT. 
(WITH SIX FIGURES) 
No subject is of more general interest to botanists than the 
early race-history of angiosperms. In a recent paper’ I have 
attempted to justify the publication of a new hypothesis on this 
subject by a detailed account of the embryological evidence on 
which it is founded. The details of such work, however, have 
little interest for any but specialists, and I wish to deal here with 
the wider aspects of the subject. The argument of the follow- 
ing pages is in substance that contributed to a discussion on the 
evolution of monocotyledons which was held in September, 1903, 
at the Southport meeting of the British Association for the 
Advancement of Science. The whole paper has been recast 
since then, much has been added, and something omitted ; in par- 
ticular several passages have been introduced in answer to 
objections raised during the discussion. 
There is a remarkable absence of direct geological evidence 
concerning the origin of angiosperms and the comparative antiq- 
uity of the two races included in that group. In the present 
State of our knowledge all conclusions with regard to the race- 
history of angiosperms must be founded on the comparative 
morphology of living forms. On such grounds, however, I have 
ventured to assume that monocotyledons and dicotyledons will 
ultimately be traced back to a common ancestor which in all 
Annals of Botany 17:I. 
aia E., A theory of the origin of monocotyledons. 
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