360 E. OC. ANDREWS. 
characterised the Cretaceous Period, and that it had caused 
the rapid rise and differentiation of the angiosperms, 
together with their dispersal throughout the world. In 
this development insects possibly played a great part. 
Inasmuch as the Leguminosz, especially the Papilio- 
nacee, are highly developed members of the Dicotyledons, 
it would appear that they had no existence during the 
Lower Cretaceous. 
Taubert,* in Pflanzenfamilien, records the existence of 
Leguminose remains, as fossils, from sediments of unknown 
age. It is thought the age may be Tertiary. It is difficult, 
however, to classify dicotyledonous fossils in the absence 
of full material. Reports have been made by Heer, Unger 
(61) and Ettingshausen (32), in which certain Upper Creta- 
ceous and Tertiary fossils of dicotyledonous types have 
been referred to existing families, and even to living genera, 
from the evidence of leaves alone in the main. All such 
determinations should be treated with the utmost caution. 
It is very difficult to classify many modern dicotyledonous 
types, even with full and abundant material and a know- 
ledge of the growing plants. For example, the genus 
Krameria is now placed in the Leguminose, nevertheless 
the great systematist, Bentham, referred it to the Poly- 
galeze; Lindley was inclined to place it among the Sapin- 
dacez, because of its trifoliolate leaves, but Asa Grey 
pointed out that trifoliolate leaves were characteristic, 
also, of certain tribes of Leguminosee. Other examples 
might also be quoted, such as the difficulty experienced by 
systematists in classifying Chamalauciez and Lecythidee, 
as also the genera Trigonia, Podogonium, and Acicalyptus. 
The leaves of Hakea, Persoonia, Grevillea, Acacia and 
Kucalyptus may also be cited as consisting of varied forms. 
1 (60) p. 385. 
