The pink-and-green tide of preppiness that washed over the country last year may have tickled the fancies of countless Muffys, Buffys and Sissys, but it also raised some healthy profits for a woman who hardly needs them: Lilly Pulitzer of Palm Beach. Daughter of a prominent horse-racing family and former wife of a newspaper heir, the independent Lilly has made her fortune selling blindingly bright floral prints splashed on her sportswear and trademark shifts in 31 Lilly Pulitzer shops nationwide. Her annual gross: approximately $15 million.

Lilly started from the bottom—not financially, but emotionally. Back in 1957 she was 26, filthy rich, married to press lord Joseph Pulitzer's playboy grandson, Peter, and miserable. "I loved a good time," she says, "but Palm Beach society wasn't it." The situation landed Lilly in a Westchester, N.Y. mental hospital for six months of analysis. "I went crazy," says Lilly bluntly. "I was a namby-pamby; people always made decisions for me. The doctor said I should find something to do."

Three years later, she did. The millionaire matron started selling oranges and grapefruits grown in Peter's Florida groves from the backseat of the family station wagon. The activity prompted admiration from neighbors. A few months later she began selling juice. "Since I spent my days squeezing fruit, I was always covered with juice," recalls Lilly. "So I designed myself a cotton shift in colors that matched the fruit."

Her shockingly flamboyant orange-yellow-and-green print shift was slit on both sides for comfort, fully lined (so that there was no need for underwear), topped with a bow and backed with a zipper. It got so many compliments she asked her dressmaker (Lilly can't sew) to whip up 20 shapeless shifts in green-and-pink florals and red-and-blue prints and stripes to sell along with the fruit. "They took off like zingo," she reports. "Everybody loved them, and I went into the dress business."

The Lilly, as Pulitzer's trademark smock came to be known (syndicated columnist Eugenia Sheppard called it "a cross between a chemise and a muumuu"), has been worn by the moneyed likes of Jackie and Rose Kennedy, Dina Merrill and Happy Rockefeller. While the $60 to $120 shift remains Pulitzer's staple, this summer Lilly is also offering snappy sun dresses, silk sheaths, off-the-shoulder dresses and blouses and short-sleeved sweat shirts for the prep set. Skirted-bottom bathing suits ($79) will share the rack with sexy maillots ($42), peasant blouses ($50) and knit tops ($22).

Nor has Lilly neglected the preppy male. George Plimpton, Bob Hope and Joe Namath all sported her wildly flowered pink-and-blue PJs (Pulitzer Jeans) more than a decade before Brooke Shields wiggled into her first pair of Calvins. Lilly named her men's night—shirt Sneaky Pete after Peter ("It seemed fitting"). They divorced in 1969. "We had nothing in common," says Lilly. "He was always away hunting, fishing or flying his plane." That same year she married Enrique Rousseau, now 65, a Cuban lawyer and rancher who recently retired from managing a Howard Johnson's motel in Miami that Peter owns.

One of three daughters born to Lillian and Robert McKim, Lilly lived a charmed childhood in Roslyn, N.Y. and Palm Beach even before her parents divorced and her mother married Ogden Phipps, a noted Thoroughbred owner. After graduating from Miss Porter's School in Farmington, Conn. (Jackie O was a schoolmate), Lilly worked briefly as a nurse's aide at New York's Bellevue Hospital Center before marrying Peter in 1952. "I was a gypsy, living a carefree life of ponies and tennis," she remembers. "I wore jeans while others dressed up."

Little has changed. She loves to run in the sand and used to walk barefoot almost everywhere. A night out means "going hog-wild," singing, dancing and drinking vodka in Palm Beach saloons or at the homes of friends. "Lilly sits on my lap while I play the piano," says society bandleader Peter Duchin, a pal for 30 years. "She's an original with a great sense of humor."

Lilly and Enrique are building a spacious villa in Palm Beach where she will spend as much time as possible with her children, Peter, 28, Minnie, 26, and Liza, 25, her two grandchildren and Enrique's three grandchildren. She has a maid and a gardener, skips up to New York four times a year, and visits either Europe or South America for a month each fall. "I'm lucky, I guess," she says. "But I never really enjoy vacations. I need the energy and excitement of my business."