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CACTACEZ OF THE UNITED STATES. 
Tue only Cactus known to Linnzus from the countries north of 
Mexico was his Cactus Opuntia (Opuntia vulgaris). Long after 
him, more than forty years ago, Nuttall, the pioneer of West Ameri- 
can botany, discovered two Mamillarie and two Opuntie on the 
Upper Missouri, and again, twenty years later, in California, a new’ 
Echinocactus. About ten years ago we became acquainted with nu- 
merous new Cactacez, in Texas through Mr. F. Lindheimer; in New 
Mexico through Dr. A. Wislizenus; and in Northern Mexico through 
the same explorer and Dr. J. Gregg : some others (and among them 
the giant of Cacti) were indicated in the Gila country by the then 
Lieutenant W. H. Emory. Soon afterwards Mr. A. Fendler col- 
lected several new species about Santa Fé. Mr. Charles Wright, 
a few years later (1849), discovered in Western Texas and Southern 
New Mexico-still other undescribed Cacti. 
But the greatest addition to our knowledge of the Cactacee of the 
southern part of the United States was made by the gentlemen con- 
nected with the United States and Mexican Boundary Commission, at 
first under Colonel Graham, and subsequently under Major Emory. 
Science is indebted principally to Dr. C. C. Parry, Mr. Charles Wright, 
Dr. J. M. Bigelow, Mr. George Thurber, and Mr. A. Schott, for val- 
uable collections of living as well as anes specimens, and for full 
notes taken on the spot. 
About the same time, Mr. A. Trécul of France, and after him Dr. 
H. Poselger of Prussia, traversed Southern Texas and Northern Mexi- 
co, collecting many Cact , and increasing our knowledge of this 
interesting branch of botanical science. | 
Pacific Railroad expeditions since 1853 have opened fields not 
