354 E. C. ANDREWS. 
Milletia, Clianthus, Swainsona, Glycyrrhiza, Desmodium, 
Uraria, Lespedeza, Glycine, Erythrina, Galactia, Vigna, 
Atylosia, Rhynchosia, Flemingia, Dalbergia, Lonchocarpus, 
Derris, Sophora, Mezoneurum, Pterolobium, Oassia, Bau- 
hinia, Afzetia, Erythrophlocum, Adenanthera, Neptunia, 
Acacia, Albizzia, and Pithecolobium. 
From this list the systematist will note the absence of 
Hriosema, Smithia, Zornia, Mimosa, Oalliandra, Inga, 
Dolichos, Auschynomene, and other well known and widely- 
spread genera. It would appear as if Australia had been 
isolated from the tropical world before the differentiation 
of these types, and that the species belonging to such 
forms as Aischynomene, Smithia and Zornia, now found 
in Australia, are either colonists or waifs. 
It is possible also that the thirty-five genera enumerated 
above were established in Australia before the development 
of the thirty-five endemic genera of that continent, and 
that they are examples of arrested development, whereas 
the endemic forms are vigorous, but younger types, which 
only appear to be ancient and archaic by reason of their 
stunted and weather-beaten aspect. 
This statement concerning the probable great age of the 
pantropical genera of Australia, and the relative youth of 
the endemic legumes of Australia, and South Africa, is not 
so remarkable as might appear upon first consideration, if 
a co-ordination be made of the principles upon which plant 
distribution and development depend. But before a dis- 
cussion of these it will be advisable to mention the main 
features of the Cretaceous and Post-Cretaceous geography 
and climate. After a brief discussion has been presented 
in a later chapter of the principles of geographical distri- 
bution, the way will be open for a consideration of both the 
home and the nature of the primitive types, and some 
insight may thus be gained as to the lines along which the 
development of Leguminosze appears to have taken place. 
