28 BOTANICAL GAZETTE ; [JANUARY 
by many to be due to response to the peculiar environmental 
conditions surrounding the former. 
14. Theories differ especially as to whether amphisporangiate, 
entomophilous flowers bearing a perianth, or naked, anemophilous, 
monosporangiate ones are primitive among dicotyledons. The 
writer holds, for reasons given, that in the remote past the ancestors 
of the dicotyledons (and so of all angiosperms) possessed naked, 
unisexual flowers, but that among existing groups hermaphrodite 
flowers provided with a perianth are primitive, and that the naked, 
unisexual forms existing today have been secondarily derived 
from the latter; moreover, that the appearance of entomophily, 
the amphisporangiate condition, and the perianth have been very 
important features in the evolution of modern angiosperms. 
15. The Bennettitales, Gnetales, and angiosperms may have 
had common ancestors if we go back to a time prior to that when 
the Bennettitales became a distinct line. It seems reasonable to 
conclude either that angiosperms were derived from the same 
ancient fern stock from which the Cycadofilicales originated, or 
else that they were differentiated from the Cycadofilicales at a 
very early time. 
16. In conclusion, it is believed that the most primitive of 
existing angiosperms are to be found among the Magnoliaceae or 
related forms, and not among forms with naked, monosporangiate, 
anemophilous flowers. 
RANDOLPH-MACON COLLEGE 
As 
ND, 
LITERATURE CITED 
AnpREws, F. M., Karyokinesis in Magnolia and Liriodendron with 
special PTE ‘6 behavior of chromosomes. Beih. Bot. Centralbl. 
II: 134. 
ARBER, E - NEWELL, and PARKIN, JoHN, On the origin of angio- 
rms. Jour. Linn. Soc. Bot. 38: 29-80. 1907. 
Brown, Writ1am H., The nature of the embryo sac of Peperomia. Bot. 
Gaz. 46: 445-460. I 
4. CAMPBELL, D. H., Recent investigations upon the embryo sac of angio- 
sperms. Amer. Nat. 36: 777-786. 1902. 
Coutter, J. M., Relation of megaspores to embryo sacs in angiosperms. 
Bor. Gaz. 45: 361-366. 1908. 
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