THE ORIGIN OF ANGIOSPERMS. : 15 
GENERAL CONCLUSIONS AND SUMMARY. 
From a general survey of existing Angiosperms, we have arrived at the 
conclusion that the Apetalous orders without perianth, such as the Piperales, 
Amentiferous families, and Pandanales, cannot be regarded as primitive 
Angiosperms. We thus dissent entirely from the current view, advocated 
especially by Engler.  Engler's theory is criticised on three grounds. 
Firstly it presupposes that the perianth must arise de novo, and be an organ 
sui generis. On the contrary, we surmise that the perianth is an ancient 
structure, present in the fructification of the immediate ancestors of the 
Angiosperms. In the second place, the so-called primitive flowers of the 
above orders are invariably accompanied by a complicated and highly-evolved 
inflorescence, which we are unable to regard as a primitive character. Thirdly, 
such a theory is phylogenetically sterile, for, while it has the merit of simplicity, 
it does not afford any clue to the ancestry of the group, nor does it tend to 
bring the living Angiosperms into line with the fossil plants of the past. 
On our view, the primitive and typical Angiospermous fructification is a 
special form of amphisporangiate cone, distinguished by the peculiar juxta- 
position of the mega- and microsporophylls, and by possessing a well-marked 
perianth. А strobilus exhibiting these features we term an Anthostrobilus. 
The word “flower,” which in our opinion should be restricted to the Angio- 
sperms, is used in a great variety of senses. The flower of members of this 
group is regarded as a special form of the Anthostrobilus, and may be dis- 
tinguished as ап Eu-anthostrobilus, o£ which the distinctive features are the 
presence of the special type of microsporophyll termed a stamen, and of closed 
carpels. On our view, however, an earlier form of Anthostrobilus is to be 
found among Gymnosperms, where, however, the megasporophylls are not 
closed, and the microsporophylls have not the form which can be called 
stamens. We designate this latter type a Pro-anthostrobilus. This is the 
form of cone possessed by the Mesozoic Bennettitew, and also we believe 
by the hypothetical, direct ancestors of the Angiosperms, or, as we here term 
them, the Hemiangiospermee. 
On the strobilus theory of the primitive Angiospermous fructification, we 
find, when we turn to the fossil evidence, that it is possible to trace the 
descent of living Angiosperms in its broad outlines. The direct ancestors of 
this group (the Hemiangiospermez) are unknown as yet in the fossil state 
But on this theory we recognise in the Pro-anthostrobilus of the Mesozoic 
Bennettitee, which we regard as closely related to the Hemiangio- 
spermex, features which enable us to restore in some measure the missing 
fructification of the ancestor. We are helped in this task by what we have 
termed the law of corresponding stages in evolution, which states that 
equivalent stages in the evolution of the different organs of one and the same 
seed-plant are not contemporaneous in point of time. This has proved 
