A six-piece jazz band called Hot Mustard, playing tunes associated with Louis Armstrong, Duke Ellington, Jelly Roll Morton, two Smiths -- Bessie and Kate -- and other classic performers, entertained a lawn covered with picnicking diners in the courtyard of the National Portrait Gallery last night. The weather was balmy, the crowd attentive and the music a spirited retrospective (with running commentary by leader Dave Burns) of an era that had its storms but looks rather placid from the perspective of these turbulent headwaters.

Tightly packed ensembles ("Wolverine Blues"), relaxed swing (" 'Deed I Do") and frequent solo spots combined for an opening set of variety and balance.

Trumpeter Sonny James' angels-on-high lead on "Cornet Chop Suey" scattered the clouds. Mason (Country) Thomas' clarinet was the thread that stitched together the polyphony on many numbers, and his tenor sax on "Moon Song" had a Coleman Hawkins girth and a Ben Webster eroticism. A powerful left hand and a traveling right were pianist John Philips' strong suit, and bassist Jim Ford walked a steady line right down the middle of the road. George (Dude) Brown's half rolls, cymbal ride and shuffle bass drum kept the action moving with authority. Trombonist Burns contributed period vocals that essayed jazz chestnuts, pop of yesteryear and the blues.