THE ORIGIN OF ANGIOSPERMS. 29 
~ a 
On the Origin of Angiosperms. By E. A. NEWELL АЌвев, M.A., F.L.S., 
Trinity College, Cambridge, University Demonstrator in Palæobotany, 
and Јонх Parkin, M.A., F.L.S., Trinity College, Cambridge. 
(With 4 Text-figures.) 
[Read 21st March, 1907. | 
CONTENTS. 
Page 
Introduction ааа. 29 
Historical ,,................................................ 31 
Principles of Evolution ...................................... 34 
The Law of Corresponding Stages in Evolution .............. 85 
Homoplasy oo. eet eee eee 35 
Mutation ,.,,....................-з ажа. hh 36 
Primitive Features among Living Angiosperms .................. 36 
The Strobilus Theory of the Angiospermous Fructification .... 86 
Engler’s Theory ........... sese 38 
Piperales .......................................... 39 
Amentifer& ........................................ 40 
Monocotyledons .................................... 42 
The Primitive Form of the Organs of the Eu-anthostrobilus or 
Flower ........... eeemoesessessseestbusseseeeese 43 
The Megasporophylls and Megasporangia ................ 47 
The Microsporophylls and Місгозрогапоіа .............. 48 
The Perianth ........... еее HI 48 
Fossil Evidence ............................................ 51 
The Bennettitee ........................................ 52 
Previous Interpretations of the Bennettitean Strobilus ........ 55 
The present Interpretation of the Fructification of the 
Bennettite& ........................................ 58 
The Hemiangiosperme ...................................... 62 
The Origin of the Angiospermee .............................. 64 
The Gyngceum .............................nasnamenasa 65 
The Andrecium ........ een 67 
The Perianth ...... еее Hmm 68 
The Angiospermous Type of Foliage ........................ 69 
The Origin of Monocotyledons ................................ 71 
Entomophily 2.0.0... cece cece nee hmmm 73 
General Conclusions and Summary ............................ 75 
Bibliography еек mnm 77 
INTRODUCTION. 
THE recent progress in our ideas as regards the phylogeny of the Gymnosperms, 
and more especially of the present day Cycads, led us, in 1908, to begin an 
enquiry into the origin of Angiosperms. During the last three years we have 
devoted considerable attention to the living members of this group, for it was 
thought that the attack could be best begun by taking as broad a survey as 
