Genera florae Americae boreali-orientalis illustrata : the Genera of the plants of the United States illustrated by figures and analyses from nature by Isaac Sprague ... Vol I (plates 1-100)
Isaac Sprague. Boston, Massachusetts: James Munroe and Company 1848. First Edition. 230, [2-blank] pages + 100 plates (plate 27 bound out of order between plates 21 and 22). 8vo. Publisher's brown cloth gilt. Soiling to the binding, clumsy repair to top several inches of spine panel. Rear joint starting at top. Engraved black and white plates are clean and nice excepting the first few which have green scuffs on them. Opens more easily at the division between text and plates (lining showing in the gutter), but still sound. Good. Cloth. 
Issued a year apart, we offer volume one ONLY which contains the first 100 (of an eventual 186 total).
Asa Gray was a prominent botanist. He taught at both Harvard and the Lawrence Scientific School for 30 years. "Gray became the leading botanical taxonomist in America in the nineteenth century ... because the American setting demanded priority for a program of classification on a continental scale to match the programs of European nations in all parts of the globe not served by local collectors."
Dictionary of Scientific Biography, Vol 5/6, pp 511-514.