An oil painting that had been on loan to the Smithsonian for more than 60 years, and had stirred a courtroom battle over its rightful owner, was sold here today at Christie's auction house for $330,000.

Frederic Edwin Church's "South American Landscape" (1856) was consigned for sale by the estate of Theresa Davis McCagg. McCagg, a Washington social figure during the first quarter of this century, lent the picture to the Smithsonian in 1917, and that's where it remained until 1977, when James Maroney, an enterprising New York art dealer, spotted the Luminist landscape hanging in the National Museum of American Art with a plaque indicating it had been on loan all those years.

In October 1979, a much larger Church painting, "Icebergs," sold at a New York auction for $2.5 million, a record price for an American painting. That sale apparently fueled Maroney's five-year campaign to recover the "Landscape."

After discovering that McCagg had died in 1932 without referring to the painting in her will, Maroney tracked down McCagg's heirs and alerted them that they owned a valuable painting. But the Smithsonian refused to release it. After a protracted legal wrangle, on June 8, 1981, a D.C. Superior Court judge ordered the institution to return to the McCagg estate that painting and another painting that was on loan.

Maroney's efforts, however, bore no fruit for him. He said today in a phone conversation that he lost control of the painting, which he had intended to sell himself, and which he believes to be worth $500,000 retail. "I didn't go to all this trouble to bring the picture out to have it sold at auction," he said. "It's been a very frustrating experience."

Spokesmen for the family were unavailable for comment, and a spokesman for the Smithsonian refused to comment.

"South American Landscape," which was purchased by New York's Kennedy Gallery, was one of two key lots in a sale of American paintings at Christie's, the London-based fine art auction house. More than 200 works of art, ranging from early landscapes of unspoiled America to peppy Norman Rockwell illustrations -- and including five outstanding Winslow Homer watercolors -- were sold for a total of $5,255,140 and, with one notable exception, the house was pleased with the results.

"After the Hunt" (1883), a rare hunting still life by William Michael Harnett, failed to sell, even though bidding in the room reached $1 million. The painting is one of four examples from Harnett's "hunt" series. The other three are in museums, and the house and the consignor expected the painting to bring at least $1.2 million. The consignor, who chose to remain anonymous, reportedly offered the picture because his wife feels it is "too gamy," as it depicts dead wild fowl and a gun and bugle hanging on an oak door.

"Sponge Boats, Key West" (1903), a small watercolor by Winslow Homer, fetched $561,000, the highest price in the sale and a record price at auction for an American watercolor. Homer's "Blythe Sands," a charcoal, gouache and pencil study of two maidens on the beach, brought $140,000. Ruth Carter Johnson, of the Amon Carter Museum in Fort Worth, purchased the picture for the museum. It was her first time bidding at auction, and she said after the sale she felt a little shaky.

"Santa" (1965), a festive Norman Rockwell illustration of Santa Claus holding a bottle of Pepsi, brought $5,500. The auction of the Rockwell ended today's eventful sale -- the last major one of the fall season -- on an appropriate holiday note.