26 THE AMERICAN NATURALIST. (VoL. XXXIX. 
before any careful work had been done on the cryptogams. As 
a result an interpretation of the angiospermic embryo was 
evolved wholly from evidence obtained from angiosperms and 
without reference to any evidence which cryptogamic embryos 
might furnish. This interpretation in the hands of the system- 
atists soon became a fixed creed which has come down to the 
present day as built upon facts too well established to be 
questioned. Some morphologists have, it is true, attacked this 
creed, but have failed to lessen in the slightest degree its 
general acceptance. 
Because the cotyledons of certain plants assumed the func- 
tion and approximated the form of leaves, a morphological leaf- 
value was, from the first, ascribed to them. This hypothesis, 
framed on simple analogy, is the self-evident fact which consti- 
tutes the basis for all later acceptable embryological considera- 
tions. If cotyledons are morphologically foliage leaves, that the 
most primitive angiosperms must be those of which the cotyle- 
dons most nearly approach foliage leaves, is a conclusion which 
naturally followed. And hence the creed recognized the dicoty- 
ledons as the most primitive and considered the monocotyledons 
à race derived from them. Some theorists would derive the 
monocotylous condition from the dicotylous, by the abortion of 
one cotyledon, and others, through the fusion of the two cotyle- 
dons into a single member. | 
Following, and followed by others, the writer has concluded 
that cotyledons are not metamorphosed foliage leaves. The 
writer has further suggested that they are primarily haustorial 
organs originating phylogenetically as the nursing-foot of the 
Bryophytes and persisting throughout the higher plants; that 
the monocotylous condition is the more primitive and that the 
dicotylous condition has arisen through a bifurcation of an origi- 
nally single cotyledon, 
There are, it is true, certain dicotyledons which show a ten- 
dency to reduce one cotyledon and others in which a partial or 
complete fusion of the cotyledon petioles undoubtedly takes 
place, yet there is no evidence to 
tion of either process in ex 
lous condition. 
justify the sweeping applica- 
plaining the origin of the monocoty- 
