INTRODUCTION. 



THE State of Texas, an empire in itself, comprising one-twelfth of the 

 area of the United States, with great diversity of soil and climate, must 

 necessarily present a corresponding diversity in plant life. When all of 

 its immense area is thoroughly explored, it will undoubtedly yield as 

 many or perhaps more species than are contained within the limits of 

 Gray's Manual. 



As is stated in the Introduction to the Botany of the Mexican Bound- 

 ary Survey, a line drawn from the Pan Handle southeast to the vicinity 

 of Corpus Christi, divides the State into two unequal portions. The 

 smaller eastern part is well watered as a whole, and gives rise to more 

 luxuriant vegetation than the other, where rain is uncertain and often 

 scanty. The flora of this eastern section, at least in its northern and 

 eastern portions, has many species in common with the adjacent States 

 of Louisiana and Arkansas and the Indian Territory. 



The larger southern and western division, in many places a veritable 

 desert, contains many peculiar plants, found only within its limits, es- 

 pecially in the central portions, in the limestone foothills, and in the 

 mountains of the extreme western part. Along the southern border, the 

 species are essentially Mexican, intermingling in the mountain region 

 with more northern forms found in the mountains of New Mexico, and 

 with characteristic Texan plants. 



Undoubtedly the best part of the State botanically, and also the least 

 known, is the extreme southern portion, from Corpus Christi west to 

 Laredo and south to Brownsville. In the Mexican Boundary Survey, 

 the statement is made that "the botany of this region is too well known 

 from various published accounts to require further details in this place." 



Nevertheless, the fact remains that practically we know nothing of 

 what it contains. The bulk of Neally's new species were collected be- 

 tween Brazos Santiago and Rio Grande City. Between the latter place 

 and Laredo I find no mention of plants ever having been collected. 

 The rough character of the country, its inaccessibility, drynesss, and the 

 great expense to be incurred in properly working it up, are formidable 

 barriers to an individual explorer. 



Corpus Christi Bay and the lower Nueces may be considered the 

 northern boundary of this interesting tract of country. The vegetation 

 so characteristic of a dry country is very marked, nearly everything being 

 armed with thorns or spines. At Corpus Christi, where in all, eight 



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