i 



8 



very plentiful. Next come Euphorbiaceae with about 25 species, La- 

 biatae with 20, and Umbelliferae and Cruciferae with 12 or 15. 



As before mentioned, Corpus Christi Bay and the lower Nueces may 

 be considered the northern boundary of a flora peculiar to southern 

 Texas. Within the limits of this, six of my eleven new species were col- 

 lected, and a number of rare ones re-discovered. 



Between this and the more elevated limestone district, is a tract 200 

 miles wide at some places, which appears to have a flora more or less 

 distinct from the other two sections, although many species common to 

 both are found within its limits. My knowledge of this central tract 

 was obtained principally from observations made along the railroad while 

 traveling. Here the Mesquite is much more abundant than in the south- 

 ern section, while in the limestone region proper it seems to be entirely 

 wanting. 



At San Antonio, or rather a few miles west, the limestone formation 

 and hilly ground begins, with a distinct and sharply marked flora, the 

 Mesquite and other plants so common and rather monotonous suddenly 

 giving place to groups of Sapindus, Monarda citriodora, etc. 



My thanks are due to Mr. Frederick V. Coville, Government Botanist, 

 who kindly gave me the opportunity of making my determinations at 

 the U. S. National Herbarium, and determined the fund; to Mr. J. N. 

 Rose, who determined the Umbelliferae ; to Prof. F. Lamson Scribner, 

 for the determination of the grasses ; to Dr. N. L. Britton, for the use of 

 the botanical library of Columbia College and of the herbarium while 

 making corrections and final determinations ; to Mr. John K. Small, for 

 the determination of the Polygonums and Rumex ; to Dr. Thos. C. Por- 

 ter, for the determination of 100 of the first numbers, and to Mr. M. S. 

 Bebb, for the determination of the willows. Without the aid of these 

 gentlemen, it would have been impossible to produce the present work. 



In the matter of citations of publication, it is to be regretted that in 

 perhaps a dozen cases the date could not be obtained. Certain numbers 

 of the Botanical Magazine and Botanical Register could not be con- 

 sulted, as well as several other works. 



Apology must be made for the unnecessary omission of many type 

 localities. The first part of the enumeration was prepared before I had 

 access to the original descriptions, and later this omission was over- 

 looked. 



The last line in the paragraphs under the enumeration and descrip- 

 tions of species refers to the date of collection and the number of the 

 plant, the latter in parenthesis, as " May 26 (1781)." 



