BIG TIMBER (AP) — Four flowers that were collected and pressed by Lewis and Clark 200 years ago will be on display this summer at the Crazy Mountain Museum here.

The museum will celebrate the bicentennial of the Lewis and Clark expedition on Memorial Day by unveiling the flowers and an educational garden devoted to all the plants the explorers gathered in Montana.

‘‘It’s a very special festival,’’ said Sandi Blake, head of the local Lewis and Clark Commission. ‘‘It’s not like this happens every day here.’’

The pressed flowers to be displayed — the bitterroot, the blue flax, the purple prairie clover and snow-on-the-mountain — are on loan from the herbarium at the Academy of Natural Sciences in Philadelphia.

The purple prairie clover was gathered near Cut Bank Creek in Glacier County on July 22, 1806, and is accompanied by Lewis’ original notes.

‘‘The Indians use it as an application to fresh wounds. They bruise the leaves adding a little water to apply it,’’ the explorer wrote.

Blake sent a letter to the academy requesting the flowers in 2002. Before the academy would agree, the Crazy Mountain Museum had to install security cameras, an alarm system and a custom-built display case with special lighting and temperature and humidity controls. The museum also had to insure the flowers.

Getting the plants to Montana required construction of a $400 wooden box and the use of a semi tractor-trailer designed for transporting art and other treasures.

‘‘It was quite expensive,’’ said Helena Pedula, museum board chairwoman. ‘‘We had to pay for a certain amount of square feet for the box. It had to be set flat in the bottom of the truck with nothing around it.’’

The museum’s newly planted educational garden contains interpretive signs and all the plants collected by Lewis and Clark that the area can grow. The National Park Service has recognized the garden as an official stop on the Lewis and Clark National Historic Trail.

Other festivities at the Memorial Day event include a book signing by Montana botanist Wayne Phillips; the release and cancellation of a Lewis and Clark expedition commemorative stamp; and a barbecue lunch.

The pressed flowers will remain on display at the museum until Labor Day. Admission to the museum is free.