Lilly Pulitzer, the accidental fashion designer who dreamed up the Lilly, the raucously colored, simply cut frock that since the 1960s has filled the closets of women who live or wish to live in an eternal summertime, died April 7 at her home in Palm Beach, Fla. She was 81.

Gale Schiffman, a representative from Quattlebaum Funeral and Cremation Services, confirmed the death but did not disclose the cause.

By the time of Mrs. Pulitzer’s death, the story behind the Lilly — that unmistakable shift with plain lines, and palette of fuchsia, lime, chartreuse and orange — had become one of the most celebrated tales in the fashion world. With its elements of whimsy, and a supporting role for first lady Jacqueline Kennedy, it went like this:

Mrs. Pulitzer was the daughter of a Standard Oil heiress and married — eloped, actually — into the Pulitzer newspaper family. She was a well-to-do housewife and mother of three humming along in her comfortable but evidently unsatisfying life in the 1950s when she suffered, unexpectedly, what has been described as a nervous breakdown. A doctor advised her to get a hobby.

She had always been something of an anomaly in the high-class milieu of Palm Beach, with her barefoot strolls down the main shopping boulevards and her practice, while entertaining in her home, of dousing the floor with water to facilitate dancing. In keeping with her unusual tastes, Mrs. Pulitzer chose what might have seemed at the time a curious divertissement: She would peddle the oranges grown in her husband’s citrus groves.

Soon she was running a fruit stand in Palm Beach, an operation that often left her clothing sullied by orange and pink juices. She went to the five-and-dime store, selected a printed fabric that would hide the stains, and asked a seamstress to fashion her a dress.

Mrs. Pulitzer’s customers liked the look — two seams, a few darts, a slit to facilitate the manual labor associated with her job. Sensing a ripe market, Mrs. Pulitzer began selling dresses from her stand along with her fruits and juices.

In a little more time, the dresses became more popular than the rest of her wares, and Mrs. Pulitzer no longer ran a citrus stand, but a fashion enterprise. A key partner was her friend Laura Robbins Clark, a former fashion editor.

The Lilly debuted in 1959. It was conspicuous, comfortable, and conspicuously comfortable, much like the lifestyle of the affluent women the Lilly was often said to represent. Patterns featured a taxonomy of tropical flora and fauna.

In accordance with Mrs. Pulitzer’s reported preferences, the dress went well with bare feet and was lined, in order not to require underwear.

Gaining popularity in the 1960s, the frock received an unexpected boost when Jacqueline Kennedy — Mrs. Pulitzer’s former classmate — appeared in Life magazine clad in a Lilly. The first lady and her daughter, Caroline, once wore matching Lillys. The family’s matriarch, Rose Kennedy, also joined the craze, as did women across the country.

The Lilly proliferated first through the resort class and eventually across the country through dozens of boutiques and sales in department stores such as Saks Fifth Avenue and Lord & Taylor. Swimsuits, pajamas, handbags, children’s and men’s clothing and home wares followed.

“Now if there is one special thing Lilly Pulitzer should be given credit for,” read a 1966 Washington Post article, “it is this: She changed the summer uniform of countless thousands of American women who once wore flower printed cotton shirts, wrap around skirts and big, klonky, thick-soled loafers. The total look was usually that of a shirt tail flapping out awkwardly in the back.

“Lilly Pulitzer,” the article continued, “neatly put a stop to all that.”

Subsequent observers found even deeper meaning in the style.

“In their upside-down-beach-bucket simplicity,” read a 2003 retrospective in Vanity Fair, “Lillys blur the line between woman and child, mother and daughter, experience and innocence. Put on a Lilly and you’re the first girl in the garden, Paradise Found.”

For her part, Mrs. Pulitzer denied having a keen fashion sense.

“I couldn’t make a fashion stick if I wanted to,” she told the New York Times in 1965. “Mustards, poison greens and dark colors per se aren’t good. I could sell them to a few women who don’t know any better. But it wouldn’t last. The public wants clear, bright, non-muddy colors. It tells me. I don’t tell them.”

She did, however, doubt the need to produce clothing that was suited for the colder months.

“It’s always summer somewhere,” she was quoted as saying.

As fashions changed and neutral colors became more in vogue, the Lilly aged and no longer commanded the following it once had. Mrs. Pulitzer was forced to file for bankruptcy in 1984. But about a decade later, two businessmen bought the license from her and formed a company, Sugartown Worldwide, to revive the brand.

Mrs. Pulitzer remained a consultant after her retirement in 1993. One of the businessman, James Bradbeer Jr., told an industry interviewer that the months after the terrorist attacks of Sept. 11, 2001, had brought an uptick in sales “because people wanted something happy.”

Lillian Lee McKim was born Nov. 10, 1931, in Roslyn, N.Y. She grew up in a home that Vanity Fair described as an “English manor with a massive staff.” She had two sisters, one who went by Mimsy and the other by Flossie. Her parents later divorced.

After graduating from the private Miss Porter’s School in Farmington, Conn., she briefly attended college but found herself adrift, she said, and unsure of what she wanted to do. She left school to work as a midwife’s assistant and as a volunteer at veterans’ hospitals. She met Herbert Pulitzer, her future husband and the grandson of Joseph Pulitzer, through a friend.

Their marriage ended in divorce in 1969. That year she married Enrique Rousseau, a Cuban-born lawyer and hotel manager. He died in 1993. She had three children from her first marriage, Peter, Liza and Minnie. A complete list of survivors could not be obtained.

On at least one occasion, Vanity Fair reported, the Lilly performed a most unexpected function. Mrs. Pulitzer and Clark, her business partner, were in a plane crash while traveling to Key West. Their aircraft in the water, Clark removed her orange frock and waved it at a helicopter. From the air, the pilot spotted it.