Some friendships last a lifetime. And when those lifelong friendships, however rocky and intermittent, produce art, all the better.

The friendship between two iconographic artists of the American West — Ansel Adams and Georgia O’Keeffe — was based on their mutual love of art and nature.

Beginning this weekend, the fruits of that relationship can be seen at the Smithsonian American Art Museum in “Georgia O’Keeffe and Ansel Adams: Natural Affinities.” The exhibit features dozens of pieces of art created by the many ways the two documented the landscape of the Southwest and West.

For those unfamiliar with the artists’ friendship, the exhibit may sound like an odd pairing, with Adams known for his stark but majestic photography, and O’Keeffe more often known for her luscious and colorful flowers. But both artists were tied to the

landscape in their work, and each spent their lives capturing the West on canvas and film.

After meeting in 1929, the two became good friends even though O’Keeffe was a notorious loner, while Adams was known for being rather gregarious. Despite these conflicting traits, the two shared an interest in their craft.

“You have two people who are drawn to each other for their shared interest in landscape,” said Eleanor Harvey, chief curator of the exhibit. “Yet their personalities couldn’t be more different.”

In some ways O’Keeffe’s paintings look like Adams photos in a dreamlike state; her paintings are full of color and yet have an abstract sense to them at the same time. For instance, take Adams’ photo, “Tree and Clouds, Tucson, Arizona,” which shows a large, barren tree standing alone as pillowy clouds float behind it. The same exhibit offers us O’Keeffe’s piece “Autumn Trees — The Maples,” which shows a colorful tree on a white canvas. Where Adams’ tree looks sturdy and grand, O’Keeffe’s tree is filled with color and branches that almost wave about like arms.

Some of these similarities arose from the travels the two artists took together. “The two really defined themselves by geography,” Harvey said. Much of O’Keeffe’s work was done in New Mexico, while Adams often focused on Yosemite National Park, but they both focused on the outdoors.

“What is fascinating about this exhibition is the opportunity to see how two very different artists, with equally strong personalities, approached the same subject,” Harvey said in a release. “In O’Keeffe’s paintings and Adams’ photographs, each artist captures a similar reverence for the American landscape. Yet in each artists’s work we see evidence of their independent spirits.”

It is interesting to note that although Adams photographed parts of New Mexico that O’Keeffe showed him, she never painted Yosemite. Throughout their lives there were periods of estrangement, but the two were always drawn back together by their love of art.

“It’s a reminder to us all that sometimes the energy at that kinetic point is more important than that arm-in-arm friendship through the years,” Harvey says.

The exhibit, organized by the Georgia O’Keeffe Museum in Santa Fe, N.M., features 42 O’Keeffe paintings and 54 Adams photos. The O’Keeffe works come from both public and private collections, while the Adams pieces are on loan from the Center for Creative Photography in Tucson.

The works are grouped by artist, each featuring about 10 paintings or photos. As visitors walk through the exhibit, they’ll see a group of O’Keeffe’s work, then round a corner and see a group of Adams’ photographs. Harvey said that each group speaks to the other. “You’re in the middle of a give-and-take conversation” through the exhibit, she says.

The museum will be hosting several programs in conjunction with the exhibition, including gallery talks and performances. In addition, the museum will be hosting the Washington premiere of “A Brush with Georgia O’Keeffe,” the 2008 off-Broadway play about the painter on Nov. 1. William Wylie, associate professor of photography at the University of Virginia, will be on hand in October to lecture about Adams’ technique, and a screening of a film about Adams will be shown in November.