378 E. C. ANDREWS. 
Lotus, Spartium, Sarothamnus, Caragana, Oxytropis, 
Coronilla, Hippocrepis, Hedysarum, Onobrychis, Hbenus, 
Stylosanthes, Cicer, Vicia, Lathyrus, and Pisum, appear 
to have developed mainly in open places or in waste lands 
after the Leguminosz had been well differentiated. 
The abundance of these types in North and South America 
and their absence from Australia and New Zealand is 
discussed in the chapter dealing with the differentiation 
of the Leguminosez. | 
Nature and Home of the Ancestral Forms. 
It is probable in the highest degree that the primitive 
types of the Leguminosz may never be known except by 
inference. The important point to remember in this con- 
nection is that great changes have gone on progressively 
in both parallel and divergent directions in the dicotyledons 
subsequently to the early differentiation of the Leguminosae. 
It is not that the various families which possess the greatest 
morphological affinities with the Leguminose have origin- 
ated the one from tbe other, but rather that all have sprung 
from a few types, and have developed side by side into the 
families as they exist at present. 
The evidence, in this connection, is to be sought in a 
study of both the geographical distribution of the families, 
the Cretaceous, and Post-Cretaceous geography, as wellas 
the morphology of plants in allied families, and the youthful 
stages of both leaves and flowers of Leguminose. 
Geographical Distribution.—Within the limits of each 
family of Leguminose the tropics are characterised by the 
wide diffusion of uniform or similar types. 
In extratropical regions these uniform types have 
developed in different directions in different countries. 
Within the tropics the uniform types tend to luxuriant 
habit, while in extra-tropical regions the divergent types 
are mainly xerophytic. 
