FOSSIL ANGIOSPERMS 279 



complete display of the more primitive Arehiehlamydeae. A 

 notable introduction during the Tertiary was that of the Legu- 

 minosae. That these appeared first only as Mimosa forms is a 

 strong confirmation of the primitive character of this tribe, as 

 well as of its possible relation to the Rosaceae. 



The above facts in reference to the early history of the Di- 

 cotyledons seem to warrant the following conclusions: 



1. The modern Dicotyledons were derived from a plexus of 

 vague forms developed largely in the Lower Cretaceous and 

 known as Froangiosperms. 



2. The Cretaceous and Tertiary display is almost exclu- 

 sively made up of Areliielilamvdeae, the dominant types being 

 the mure primitive Arehiehlamydeae. 



3. The Sympetalae are practically absent from the Creta- 

 ceous and Tertiary, and represent therefore a comparatively 

 recent type. 



4. The possible appearance of Viburnum, associated with 

 Aralia, at the close of the Lower Cretaceous suggests a connec- 

 tion of LTmbellales with the Sympetalae not recognized by tax- 

 onomists. 



5. Xone of the highly specialized groups of the Archichla- 

 mydeae 'are represented in the Cretaceous and Tertiary, such a 

 family as the Leguminosae being represented by its most primi- 

 tive type, and all the types being what may be called " compre- 

 hensive." 



6. The identity of genera in the eastern and western hemi- 

 spheres indicates the absence of continental diversities, which 

 later became so striking a feature in geographical distribution, 



7. The theory that simple flowers are necessarily reduced 

 rather than primitive structures seems to have a complete refu- 

 tation in the testimony of history. 



1!) 



