PLANTS OF NORTHERN OUJARAT. 
227 
with summer ; at its commencement all the vegetation becomes fresh- 
green, and there is a great increase in the display of flowers : 33 
Warming even includes under the psilophytio formations, as Savan- 
nah forest, the Indian jungles [loc. cit. p. 299). He does not, however, 
differentiate the evergreen from the deciduous forests. We have no 
evergreen forest in our area, and the little forest that touches the extreme 
north-east corner is essentially xerdphytic and deciduous. The rainfall of 
our area is about the minimum on which forest can obtain a footing, and 
there is no evidence to indicate that any part of the Savannah formations 
was previously occupied by forest. From the opposite point of view the 
planting and protection of mango, tamarind and other trees has an 
important effect, and entirely changes the face of the country. This 
can be very well seen from the train between Talod and Himmatnagar. 
Between Talod and Prantij is a tract of waste land with scanty trees. 
From Prantij to Sonasan the country is more thickly culti- 
vated, and is under the influence of the canal, with the result that 
wherever the eye turns there are huge trees of mango, tamarind, 
Mimusops, Ailanthus, etc. After Sonasan the influence of the canal 
ceases, and cultivation if scanty, and the train passes over vast tracts of 
sandy waste, almost bushless and covered with Saccharum spontaneum , 
Perotis latifolia , Tepfirosia , and other unattractive plants. Another tree, 
the cultivation and protection of which has modified the appearance of 
a part of our area, namely the country north and west of Ahmedabad, 
is Acacir crabica. The origin of the plentiful Babhul forests is stated by 
the country people to have been the great flood of September 21, 1875, when 
the Sabarmati overflowed and the inundation spread far inland. Masses 
of Babhul branches and pods carried down by the river were deposited 
in all lowlying places. Many rice fields went out of cultivation through 
the upgrowth of Babhul, and the position was further accentuated by the 
grant of leases to .persons who would undertake to preserve and protect 
the trees until they should attain maturity. Yet another feature in 
which human agency has changed the character of the country is the 
colour and constitution of the soil. In our sand areas, wherever land 
has been under cultivation for long periods, the sand is a much darker 
colour, due to the repeated doses of manure and to the ploughing in of 
crop remains. 
Accepting Savannah as the type of our Formations, we find the 
following transitions which result solely from edaphic causes. In the 
extreme north-east deciduous forest, which we call more strictly 
xerophytic woodland, occurs on the hill tops. This, on rocky hills, 
passes into Savannah woodland ; thence into thorn Savannah where the 
soil is gravelly, and into Butea Savannah where the soil is rich and loamy, 
