It's probably easier to define almost any country's music more easily than ours - so many idioms, so many influences, homegrown and imported. The Baltimore Symphony Orchestra's latest program on its Explorer Series sensibly focuses on just three elements in American music, creating an entertaining mix.

Marin Alsop, one of the best musical tour guides in the business, covers our rich folk and hymn tune traditions with the help of Aaron Copland's timeless Appalachian Spring. The pulse and twang of bluegrass are the focus in Mark O'Connor's The American Seasons. And a visit to Duke Ellington's Harlem provides a taste of jazz and various other urban beats.

If you go

The BSO performs at 8 tonight and 3 p.m. tomorrow at the Meyerhoff Symphony Hall, 1212 Cathedral St. Tickets are $15-$57. Call 410-783-8000 or go to bsomusic.org.