1914] MANEVAL—MAGNOLIACEAE oF 
monophyletic origin of angiosperms is incorrect, a more satisfactory 
one has never been advanced. The homoplastic explanation seems 
well-nigh inconceivable. Besides, in the morphological and ana- 
tomical structure of seedlings and mature plants all dicotyledons 
are essentially alike, so most of the important differences, as has 
been indicated above, are in the flowers. Taking all the evidence 
into account then, it seems likely that all dicotyledons are of one 
stock, and that the monocotyledons have arisen as one or more 
branches of this stock. 
If then dicotyledons are monophyletic, which are the most 
primitive? If, as ARBER and PARKIN (2), WETTSTEIN (31), and 
others suppose, they have been derived from gymnosperms, from 
what particular gymnospermous stock may they have come? 
The Gnetales and more recently the extinct Bennettitales have 
each been thus designated. Even if dicotyledons originated from 
a gymnospermous stock, opinions, will differ as to which is the 
parent group, depending on whether one regards naked, mono- 
sporangiate, anemophilous flowers, or entomophilous, amphispo- 
rangiate ones with a perianth as primitive. 
The entomophilous habit seems clearly associated with much 
in the evolution of angiosperms, but it does not necessarily follow 
that primitive angiosperms were entomophilous. That anemophi- 
lous angiosperms may succeed and persist in competition with 
entomophilous forms is well illustrated by such groups as the 
Amentiferae and Gramineae. 
Few, if any, believe that the flower of any hinting angiosperm 
is like the primitive angiospermous flower. Whether this primitive 
flower was monosporangiate or amphisporangiate it does not 
follow, though this is quite possible, that any particular flower 
of today is the direct descendant of a similar type in its ancestor. 
It is certain that in many instances amphisporangiate flowers have 
become monosporangiate, and that perianths have been more or 
less completely lost. 
That the opposite may have occurred, however, is less easily 
proven. ARBER and PARKIN (2), for example, object to ENGLER’S | 
view (8) that the monosporangiate Apetalae are primitive among 
dicotyledons, by saying that ‘‘it must be assumed that the perianth 
