A model train at the U.S. Botanic Garden’s “Season’s Greenings” rides through a replica of Grand Canyon National Park. (U.S. Botanic Garden)

A small replica of Old Faithful is made of driftwood and fungus, steam rising from within. Next to it, a 40-inch-high scale model of Yellowstone National Park’s Old Faithful Inn incorporates cedar wood, grape and honeysuckle vines, oak and lemon leaves, acorn caps and eucalyptus pods.

Yellowstone is just one of about 45 U.S. national parks and historic landmarks represented in “Season’s Greenings,” the U.S. Botanic Garden’s annual holiday show, which this year celebrates the centennial of the National Park Service.

Constructed almost entirely from dried plant materials by Paul Busse’s famed garden design firm, Applied Imagination, the exhibit’s wonderfully intricate models are nestled among live plants and foliage that’s crisscrossed by choo-chooing model trains. They include re-creations of cherished natural wonders — such as the Grand Canyon, Devils Tower and Arches National Park — and well-known man-made monuments, including Mount Rushmore, the Statue of Liberty and the Alamo. Also represented are less obvious landmarks, such as Martin Luther King Jr.’s birth home in Atlanta and the circa 1959 neon “Welcome to Las Vegas” sign.

“There are a whole new generation of National Park sites and national historic landmarks that speak to the diverse American experience,” says Park Service spokesman Mike Litterst. “Places like the Maggie L. Walker site [in Richmond], that tells the important story of the first African-American woman bank president in America, I think are very important” to the exhibit.

“Season’s Greenings” also features more than 30 varieties of gorgeous poinsettias and an ornament-laden tree that is one of the largest indoor Christmas trees in Washington. But it’s the fairyland world of familiar places in miniature that is sure to inspire the most wonder.

United States Botanic Garden, 100 Maryland Ave.; through Jan. 2, 10 a.m.-5 p.m. (open till 8 p.m. Tuesdays and Thursdays, with holiday concerts most evenings), free.