Marie Selby Botanical Gardens has been harboring a secret for 40 years, and it’s ready to spill the beans in a big way.

Its newest exhibition, Selby’s Secret Garden, showcases the rare and beautiful 18th- and 19th-century botanical books and illustrations in its 40- year-old research library; until now, they’ve never been shown to the public. It’s the largest botanical library in the Southeast, says education director Jeannie Perales, with some 7,000 volumes, most of them donated from private collections. Among them are a rare book collection from the late 1700s; nearly 200 years of Curtis’s Botanical Magazines (this highly regarded annual compilation of botanical illustrations began publishing in 1787); several thousand scientific journals; and a lot of loose prints, too, including a collection from Reichenbachia, a famed series of illustrated books of orchids by Frederick Sanders, dating from the 1800s.

“It is a treasure trove,” says Perales. “It’s our secret garden, the behind-the-scenes stuff that never gets seen.”

Botanical illustrations are not only breathtakingly beautiful, they’re also scientifically accurate down to the last pistil and stamen—after all, that’s how botanists identified and recorded plants long before the camera. “They’re botanical tools,” says Perales. “That’s what makes them fascinating.”

The exhibit is divided into two parts. The first displays some of the best botanical illustrations and examples from the Gardens’ herbarium and spirits collections in the Museum of Botany & Arts in the Payne Mansion, Aug. 26 to Nov. 27. The second, meant to link the living and preserved collections, will be a showy plant and flower display in the Tropical Conservatory, from Oct. 14 to Nov. 27. That exhibit will have a Victorian theme in keeping with the time period of the botanical illustrations. “Mike [McLaughlin, horticulture director] and  Angel [Lara, assistant horticulture director] have grand plans to reimagine the conservatory with formal lines, lots of greenery, ferns and mosses, and lots of orchids, too, because that’s our specialty,” says Perales. “Plus, there will be whatever botanical curiosities are around at the time.”

To shape the exhibit, Selby contracted with curator Dr. David Berry of the Ringling Museum; Berry earned his doctorate on the history of museums, gardens and libraries at the University of Oxford.

Selby’s Secret Garden follows on the success of the 40th Anniversary Orchid Show last winter. This spring, Selby will present a blockbuster exhibit of botanical paintings by the great 20th-century artist Marc Chagall in Marc Chagall, Flowers and the French Riviera: The Color of Dreams.