EDITORIAL PREFACE. 
TuIs complete collection of the Botanical Publications of the late Dr. ENGELMANN has been 
made at the suggestion and by means of the generosity of his fellow-townsman Mr. Henry SHaAw, 
who thus rears a memorial of his old friend and associate not less appropriate than those in bronze 
and marble, commemorating distinguished men, with which he has adorned the beautiful park which 
he gives to the city of St. Louis. He thus greatly obliges and benefits the botanists of our own and 
future times ; for these publications were very widely scattered, and many of them were practically 
inaccessible to those who most needed to use them, and in their dispersed condition all were difficult 
to consult. . 
Their great extent will excite the surprise even of those who thought themselves well acquainted » 
with Dr Engelmann’s work. They are the more remarkable as being the result of studies and labors 
aside from the preoccupations and toils of a well-filled professional life, the fruit of hours which 
would naturally have been devoted to recreation and needful rest. 
The classification and arrangement of the papers, and essentially the whole editorial labor has 
devolved upon the Engelmann Professor in the Shaw School of Botany, Dr. Trelease, under my 
supervision. The labor has been long and onerous. Most of the papers were published under con- 
ditions unfavorable to proof-reading ; indeed, some of the Government publications were not revised 
by the author at all. The more serious misprints were found to be corrected in the author’s own 
copies, and there were many other corrections or slight changes; all of which have as much as 
possible been attended to in the reprint. 
It was difficult to recover the illustrations of Dr. Engelmann’s papers, but it was evidently very 
necessary to have them. Through the kind attention of Professor Baird, the Secretary of the 
Smithsonian Institution, the steel plates of the seventy-six quarto engravings of the Cactacez of 
the Mexican Boundary Survey were found at Washington, and permission was obtained to use 
them. Several of them were badly rusted, and had to be repaired at considerable expense. 
The twenty-four plates illustrating the memoir on the Cactaceze of Whipple’s exploration across 
the continent on the thirty-fifth parallel, and the three plates of Simpson’s expedition had been 
engraved or drawn on stone, and the stones were not in existence. The figures have been excellently 
reproduced by Messrs. Armstrong & Co., of the Riverside Press, who took great pains to further 
our plans. 
The original plates illustrating various octavo publications, such as the early monograph of 
- Cuscutinez, having been mainly lost or destroyed, they have been reproduced in photo-electrotypes ; 
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