Every few months, a fussy cabal of art dealers, philanthropists, lawyers and museum curators meet in the Upper East Side offices of the Pollock-Krasner Foundation "over bad sandwiches," said one. They are the Park Avenue sculpture committee, and they decide, by and large, what art gets showcased on one of the pricier streets in the world.

Currently dotting the avenue are the 25-foot-tall stainless-steel roses of Will Ryman (minimalist painter Robert Ryman's son), a placement that thrills his art dealer, Paul Kasmin. "You'll see Will on Park Avenue now, and then you'll see him in a botanical garden in Miami—and then in someone's garden in East Hampton," he bragged. Mr. Kasmin should know: Nine of the 17 artists who have exhibited on Park Avenue since 2000 are represented by just two of the city's hundreds of art galleries, his own and the Marlborough Gallery. Among other artists, Mr. Kasmin and Marlborough represent such Park Avenue vets as Robert Indiana, Jun Kaneko, Claude and François-Xavier Lalanne and George Rickey, plus Fernando Botero, whose work was exhibited on Park in 1993 before the committee was formed.

Let's just say there are significant politics, and complicated logistics, behind scoring a Park Avenue show. "Park Avenue's basically an extension of the big galleries," said sculptor Robert Lobe, who applied to show on Park Avenue before being redirected to Prospect Park. "It becomes a commercial venue."

Charles Bergman, chairman and CEO of the Pollock-Krasner Foundation and chairman of the (unrelated) sculpture committee, takes umbrage at this. A quite dapper but formal fellow, Mr. Bergman seems to take umbrage pretty easily, but especially at the notion that his group does not uphold the highest of standards. "It's quite informal and it has worked beautifully," he said of the selection process.

It's not fixed, it's relaxed, said Marlborough's president of international public art, Dale Lanzone. Entire exhibitions have been birthed by ...