"I got seriously homesick," says District native Marshall Keys, who recently returned from abroad. "I would like to travel to Europe and do the festivals, but I want to live here." Early last year, a word-of-mouth report of Keys' alto saxophone talents made its way from a jam session at Charlie's to the producer of International Jazz Week in Mainz, Germany. Keys packed up his horn, played at the summer festival and then wandered around the continent for four months. His quartet will perform today at 4 p.m. in Lettumplay's "Sunday Jazz Series" at the Lansburgh Cultural Center, 420 Seventh St. NW. John Ozment will be at the piano, Carroll Dashiell on bass and Warren Shadd at the drums.

"I had a ball," says Keys, who found that "people take jazz more seriously over there." Encounters with other American jazz musicians, including saxophonists Archie Shepp and Tony Poindexter, and "hanging out" at jazz clubs, put Keys in touch with the European jazz network. As a result, he worked at least two or three jobs a week for his entire stay, which, apart from a week's visit to Paris, he divided between Germany and the Netherlands.

He even left some of his sounds behind -- in an album to which he contributed.

"I checked into this really seedy hotel," recalls Keys of his arrival in Amsterdam, but he sat in that first night at Carnegie Hall, a popular jazz bistro where he heard that the nearby "Alto Club" needed -- you guessed it -- an alto player for three weeks. "So I got the gig," says Keys, and "the place was packed, I mean literally."