129 THE POPULAR SCIENCE MONTHLY 
Mississippi Valley. Seventeen years later, after an investigation of the 
whole genus in the principal herbaria of this country and of Europe, 
he published a systematic arrangement of all the Cuscute, giving sev- 
enty-seven species, besides a number of varieties. 
Dr. Engelmann’s authority upon the Cactacee was of the very high- 
est. He established the arrangement of these plants upon floral and - 
carpological characters. This work was carried on through a series of 
papers beginning with his sketch of the botany of Dr. A. Wislizenus’s 
expedition from Missouri to northern Mexico, and continued in his 
account of the giant cactus of the Gila, in his synopsis of the Cactacee 
of the United States, and in his two memoirs upon the southern and 
western species contributed to the Pacific Railroad Reports and to 
Emory’s “ Report on the Mexi- 
can Boundary Survey.” He 
had made preparations for a re- 
vision of at least the North 
American Cactacee, but upon 
his death much knowledge of 
this difficult group was lost. 
His papers on the American 
oaks and the Conifere are of 
| the highest interest, and are 
| some of the best specimens of 
his botanical work; and the 
same is also true of his study of 
the vines. Nearly all that we 
know of this genus scientifi- 
cally is directly due to Dr. En- 
gelmann’s investigations. 
His work is characterized 
by a minuteness and careful- 
fulness of observation, coupled 
with a nicety of discrimination 
which made him a master in 
systematic work, his treatment 
of the yuccas and agayes, the genera Juncus, suphorbia, Sagittaria, 
Isoctes, the Loranthacee, Sparganum and Gentiana giving him an 
eminence among fellows botanists to which few attain. His name 
was upon the rolls of many societies devoted to the investigation of 
a and he was the recognized authority upon those departments 
of his favorite science which had most interested him. His name 
has been given to a monotypical genus of plants, Hngelmannia, by 
Torrey and Gray. Numerous Species also bear his name. 
Shortly after Dr. Engelmann settled in St. Louis, Nicholas Rich)- 
Fic. 11. Nicuotas Rieu. 
from a photograph kindly loaned by his son, 
] 
