IN A MEXICAN TOWN; VIEW OF
THE PLAZA OF LERDO, ON THE GREAT PLATEAU.]

If the geology and topography of Mexico are marked and peculiar, the
organic world also presents its own remarkable conditions; for, as to
its _flora_ and _fauna_, Mexico is a land of transition, between North
America on the one hand and Central and South America on the other, and
contains the species of both regions, in the animal and vegetable
kingdoms.

As may well be imagined from such peculiar conditions, Mexico is a
country whose _flora_ and _fauna_ are diverse and extensive. Indeed, as
regards the former, every vegetable product found from the Equator to
the Polar Circle exist in the country. The soil, in the tropical
regions, as a result of high temperature and excessive moisture, is
deep and fertile, both from the rock-decay consequent upon such
conditions, and the deposit of organic matter from the profuse
vegetation. In the region of the high plateau the product of
rock-disintegration added to that caused by volcanic matter, and the
sediment of dried-up lagoons of very recent time, have produced a great
depth of soil in places, as before described, covering vast expanses,
and this soil is found to be of exceeding fertility under irrigation.
The conditions regarding irrigation are very marked in the region of
the Nazas. On the one hand we encounter dry, bare, and uncultivated
wastes; on the other verdant fields of cotton. Why is this? Both the
lands are of a similar character of soil, but one is above the line of
the irrigation canal, and the other below.

No description of Mexico can be complete which does not sound the
praises of her varied _flora_. The most striking characteristic of the
flowers of this land, as has often been remarked, is the richness and
brilliance of their colour. The floating gardens, and the canoe-loads
of flowers and altar adornments of such which the Aztecs used and
trafficked in, bore witness to aboriginal appreciation of these. To-day
the flower-market of the capital is one of its attractions, whilst in
the valley of Mexico not a day in the year lacks roses, lilies,
camellias, strawberries, _et hoc genus omne_.

A varied and indeed, at times, eccentric field of study is laid open
for the botanist in Mexico, for not only is there a remarkable variety
of species, but their distribution is often singular. Thus the
pine-tree is often found at low elevations upon the tropic slopes, much
below its proper _habita