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THE POPULAR SCIENCE MONTHLY
Fig. 6. Entrance of the Linnæan Greenhouse at the Missouri Botanical Garden, St. Louis, Missouri; showing the three busts of Linnæus, Gray and Nuttall.
for his "Genera of the North American Plants," which did not appear until 1818. Nuttall himself set most of the type for this work. In 1818 he started from Philadelphia for Arkansas, reaching Fort Bellepoint on April 24, 1819. He made this his center of operations, exploring in various directions and making large collections. He was taken sick with fever and on recovering made one more excursion and then set out for home, reaching New Orleans February 18, 1820. At this time he had made a journey of over five thousand miles through a country still in the undisputed possession of the Indians, and almost wholly unexplored by scientific men. Immediately upon his return to Philadelphia in 1820 he began to study his collections and to write his
