The following text is from Pioneers of science in America By William Jay Youmans
"American science owes an incalculable debt to the Geneva Revolutionary Council of 1848, that suppressed the Academy of Neuchâtel and sent to our shores Agassiz, Guyot, and Lesquereux. In the heart of Switzerland's mountain grandeur this illustrious trio first saw the light and drank of that love of Nature which, deepening with the years, peculiarly linked their lives. Agassiz had been in America two years, when he was joined by Guyot and Lesquereux, whose friendship had been formed while they were collaborators in the quaint Swiss town."
"He embarked with his wife and five children as steerage passengers, reaching Boston in September, 1848. At the earnest solicitation of that naturalist he became a member of the household of Agassiz. Here he worked upon the botanical part of Agassiz's Journey to Lake Superior, until the eve of Christmas, 1848, when, at the invitation of the eminent bryologist, W. S. Sullivant, he went to Columbus, Ohio, and, entering his laboratory, continued there the study of mosses. At the close of the year 1849, under the advice and with the co-operation of Mr. Sullivant, he made a tour of exploration among the mountains of the Southern States, for the collection of plant specimens, and secured a great variety of plants, which found a ready sale among students of botany. He was particularly successful in the collection of mosses. The preparation of the specimens, their determination and distribution, gave him employment for two years, and resulted in one of the most valuable contributions to American bryology—the Musci Americani Exsiccati, by W. S. Sullivant and L. Lesquereux. The expense of preparation and publication of this work was defrayed by Mr. Sullivant, who, taking only a few copies for presentation, allowed his colleague the benefit of the sales of the rest. Using that author's library and herbarium Lesquereux lent most valuable assistance to the preparation of Mr. Sullivant's works on the mosses of the Wilkes South Pacific Exploring Expedition, Whipple's Pacific Railroad Exploration, and the Icones Muscorum."
William Starling Sullivant
At the death of William Startling Sullivant, Asa Gray said "In him we lose the most accomplished bryologist which this country has produced, and it can hardly be said that he leaves behind anywhere a superior."