The Great Chicago Fire destroyed supplies of many songs; Chicago was the home of several important publishers of sheet music.

I searched for the original sheet music of "My Pretty Quadroon," a beautiful song with abolitionist sentiments in the original, and found a copy at the Newberry Library, Chicago.
"My Pretty Quadroon," 1863, words and music by Mrs. Mary Dodge (posted in mudcat).
The Newberry Library also is a large repository of sheet music, ephemera and historical material in their Department of Special Collections.

The Stanford Catalogues are mutually shared with the University of Texas, another large repository, with many writers' manuscripts among other materials.

"The pale aronatus" is in the sheet music Taconicus located. Many have speculated about the identity of this flower, without conclusion.