A flower found pressed between the pages of a letter from a Union captain tells an intriguing part of the story of the American Civil War.

On Aug. 14, 1864, Captain John Cornelius McMullen of the 1st Wisconsin Regiment picked the flower while stationed near Georgia, just before the Union army captured Atlanta.

McMullen sent both the letter and the pressed flower to a friend of his, botanist Increase Lapham, in Wisconsin.

"It was growing outside my tent and notwithstanding the noise of 500 pieces of artillery flourished," McMullen wrote, "and seemed to repose as sweetly at night as if its native heath was not disturbed by the tread of hostile armies."

The Wisconsin Historical Society Press recently published a book about Lapham and his work. However, the authors of the book, Paul G. Hayes and Martha Bergland, did not know about the existence of the letter or the flower.

However, that flower was part of a large collection of 1.2 million other dried plants at the Wisconsin State Herbarium founded by Lapham.

The herbarium's staff found the flower when setting up a display of plants for a reading of the book there.

"We started to read the letter attached to it," says herbarium director Ken Cameron. "The sender described the flower as 'stained with the blood of heroes,' and that really caught our eyes!"

Of course, that led many to wonder who the poetic letter sender was. Historians believe it was McMullen, who was born in Delaware or New Jersey and graduated from Lawrence University in Wisconsin. He joined the 1st Wisconsin Regiment in 1861 and fought with them all the way to northern Georgia under the infamous General William Sherman, the man responsible for capturing Atlanta during the Civil War.

The letter was written just before Atlanta's capture by the Union army.

"We are now in plain view of the great commercial city of Georgia," wrote McMullen. "My company are in the front line of works only a half mile from town and while I write shot and shells are constantly passing over us. It may be some days before Atlanta falls but in the end it must yield for the best army in the world are thundering at its gate."

McMullen finished his letter by commenting on the flower:

"This flower was moistened by the blood of heroes, for Wisconsin men have died where it was plucked."