An envelope of pressed plants arrived in the Conservation Lab recently. These are not proper botanical specimens with identifying labels, but instead, a handful of pressed flowers and leaves tucked into a postal envelope. This artifact belongs to the Sarah (Tefft) Underwood Papers housed in ISU Library Special Collections and University Archives, and even without botanical credentials, holds some intrinsic value for the collection. The envelope is addressed to Sarah Underwood’s sister, Ann Tefft, who continued to live in the family’s hometown of Kingston, RI, after Sarah and her husband moved to Princeton, IA, to try their hand at a life of farming. It’s mere speculation, but I like to imagine Sarah pressing prairie flowers and sending them back to her sister in New England as a way of sharing a piece of her new, Midwestern life with her family back home.
Our treatment goal for this fragile artifact was to rehouse the pressed plants in a safe and stable manner that limited handling, while also providing a visually appealing display. Since my knowledge of praire plants is what one might generously define as “limited,” and the treatment did not warrant consulting a specialist for plant identification, I simply arranged the plants according to size and shape in a manner that gave each one its own bit of breathing space.
The two methods recommended by the literature for securing botanical specimens to a backboard are “strapping” (using small strips of archival, pressure-sensitive tape, such as Filmoplast) or adhering the specimens with methylcelluose adhesive. Methylcellulose comes in a variety of viscosities, and the one recommended for adhering botanical specimens is Grade A with a molecular weight of 4,000.
Using a standard, flat-pack archival document box for my starting dimensions, I cut a window mat with nine openings, reserving the upper left corner for the postal envelope, which I housed in a Mylar sheath open on two sides so the envelope could be removed for closer examination if necessary. In the lower right corner, I secured a Mylar envelope containing plant fragments on a backing of Permalife buffered paper. In the other windows, I secured the pressed plants with dabs of methylcellulose.
A Note About the Three-Cent Washington Postage Stamp
Although the envelope is undated, we can speculate about when it was mailed thanks to the three-cent Washington postage stamp it bears. Congress passed a postal reform act in 1851, which allowed letters to be mailed for three cents if pre-paid (rather than the going rate of five cents for pay-upon-receipt). The three-cent Washington stamp, available in varying reddish-brown to orange shades, was printed from 1851 to 1861 by Toppan, Carpenter, Casilear & Co., a private engraving firm in Philadelphia, PA. The series included a Type I, Type II, and Type IIa stamp, which varied only slightly from one another along the outer border. The stamp on this envelope addressed to Ann Tefft is likely a Type IIa, which was introduced in 1857 and discontinued in 1861. Since it was typical to buy a pre-paid postage stamp at the time of mailing a letter (rather than purchasing a sheet or roll of stamps to keep at home, which became common later in the twentieth century), it is likely that the envelope was mailed between 1857 and 1861.
Library and Archives Preservation 
Neat housing! Did you use Mylar to protect the organized specimens, or just the envelope and loose fragments? How is the final mat stored?
Thanks! I decided against Mylar overall for three reasons. First, I was concerned about static because these specimens are so thin and fragile. Second, the specimens are still quite acidic and I didn’t want to create too tight a microclimate. Finally, the Mylar’s reflectivity when suspended above the specimens really did interfere with the experience of viewing them. So, just the tiny fragments are sealed in Mylar, and I am hoping the Permalife provides enough of an alkaline buffer to keep things stable. The mat board fits inside a flat-pack archival box, and doesn’t need to be removed from the box (in fact, I have a label on the matboard discouraging its removal) for the specimens to be viewed.