INTRODUCTION. 
BY G. C. PARRY, M. D: 
GEOGRAPHICAL DISTRIBUTION. 
Every observing traveller must have noticed how closely the peculiarities of the scenery of a 
country depend upon its vegetable productions. Not only is this true of trees and the larger 
forms of plants, but even the humbler, though apparently insignificant in themselves, have 
their share in producing the general effect. Hence the subject of the geographical distribution 
of plants is one which may command the attention of every intelligent mind, and this depart- 
ment of botany has for many an interest which the higher details of the science do not possess. 
Perhaps no region of equal extent presents more marked illustrations of the relation of the 
vegetation of a country to its topography and geology than those afforded by that lying alonz 
the Mexican boundary line. 
The usually difficult task of constructing a phytological map might here be performed with 
comparative ease, as the observer, little perplexed by a great variety or gradual blending of 
forms, involuntarily associates particular localities with the predominating and characteristic 
vegetable productions. Thus one who has ever traversed the desert table lands of the Upper Rio 
Grande will not fail to unite in his recollection of these tracts the dull foliage of the Creosote 
bush, the long thorny wands of the Fouquieria, the palm-like Yucca, and the crimson-flowered 
and spine-armed Cereus. Still less can any one, who has seen the giant cactus of the Gila in 
its perfection, ever forget the wild and singular features of the country in which it grows. The 
distinctness with which the botanical districts are defined gives an unpleasant sameness to the 
scenery of this country. The extensive plains exhibit a monotonous succession of the same 
forms, and each mountain slope and ravine presents us a collection of plants quite like those 
we have so often seen in other and similar localities. Indeed, the botanist in these regions, 
knowing what to expect in each different situation, soon loses his zeal, and becomes intent upon 
little else than overcoming space. | 
We propose to give a rapid sketch of the features presented by the vegetation of the country, 
especially noticing those plants which predominate їп, and give character to, the several districts 
into which we have divided it. 
THE LOWER MARITIME BELT. 
The flora of this strip of country is too well known to require an account here, had we the 
necessary data for describing its characteristic botanical productions. Its position being 
intermediate between the “tierra caliente” of Mexico and the gulf coast of Louisiana, gives to 
its vegetation a mixed character, partaking of that of the two extremes. Thus, while upon the 
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