DEVELOPMENT AND DISTRIBUTION OF THE LEGUMINOSZA. 401 
such as A. alpina, A. phlebophylla, and A. Dallachiana. 
The first-mentioned type is sub-alpine and xerophytic. 
Falcatze.—These are Pleurinerves possessing slender 
spikes, with phyllodia usually large and long, more or less 
falcate and with numerous parallel nerves. Formssuchas 
A. Maideni and A. Cunninghamii are included. 
The group appears to be fairly recent, and one which | 
originated in the moister portions of Northern and North- 
eastern Australia. The phyllodia are often thin, there 
being but little necessity for the storage of moisture. Many 
of the species become large and handsome trees. A.dora- 
toxylon (Spearwood) is one of the types which has become 
xerophytic, working towards the sub-arid inland regions. 
A. acuminata may be a form of A. doratoxylon which has 
migrated across the desert. A.stereophylla and A. signata 
of Bentham were classified on imperfect material, and 
may have been wrongly placed by reason of their geo- 
graphical station. 
A study of Acacia and Hucalyptus indicates that in 
numerous instances a vigorous xerophyte may, under certain 
conditions, tend to develop species which are of luxuriant 
habit. Such an impelling condition was the development 
of the plateaus and sheltered gorges of Eastern Australia 
during late and Post-Tertiary time, whereby luxuriant forms 
of Kucalyptus such as EH. saligna, H. amygdalina, and H. 
regnans, aS also of Acacia such as A. melanoxylon, A. 
Bakeri, and A. penninervis, were developed. Another 
interesting point is that certain types of Hucalyptus and 
phyllodineous Acacias under such circumstances tended to 
revert to the ancestral forms. 
A few of the phyllodineous Acacias appear to have reached 
New Caledonia, the New Hebrides, and Fiji. It is reason- 
able to explain this migration by marine transportation, 
owing to the absence of other genera, such as Kucalyptus, 
from these islands. . } 
Z—Nov. 4, 1914. 
