Lillian Carter, 85, the mother of former President Jimmy Carter and a woman who became a respected and admired national figure in her own right through her feisty independence and blunt outspokenness, died of cancer yesterday in Americus, Ga.

The former president, and Mrs. Carter's two other living children, Billy Carter and Gloria Spann, were at her bedside in the Americus-Sumter County hospital when she died shortly after 5 p.m. Mrs. Carter had undergone a mastectomy two years ago after discovery of a cancerous lump.

Her son's successful campaign for the presidency in 1976 introduced "Miss Lillian," as she preferred to be known, to the public at large as a woman of talent and energy, unafraid of doing or saying the unconventional and charmingly free of pretense in demeanor and discussion.

Both skillful and compassionate, she was a nurse first in her native Georgia and later as a Peace Corps volunteer in India. In her traits and attributes, her son saw the source for many of his own.

The daughter, wife and mother of leaders in a conservative, Deep South community, Mrs. Carter set an example of racial liberalism at a time and in a place when it took both courage and conscience to do so.

Proud of her son and his accomplishments, she was not above supplying what she saw as needed criticism from time to time. As a campaigner, her opinionated openness delighted both her immediate audiences and the public at large.

Contrasted with politicians' cautious pronouncements, Mrs. Carter's candor seemed particularly pungent and refreshing. She generally avoided policy matters, but in 1979, when asked for a solution to the Iranian hostage crisis, she replied that if she had a million dollars she would pay someone to do away with Ayatollah Khomeini.

Then, quickly repentant, she muttered: "Jimmy's going to kill me."

In small things, such as the attire of pant suits and sneakers that set off her patrician manners, and in larger matters, the strong-willed Mrs. Carter demonstrated a resolute independence that she said she tried to inculcate in her oldest child.

"Everyone worries about what other people think," she said once. "I always told Jimmy never to worry about what other people say . . . Just do right and don't worry about the gossip."

During the years of segregation, Mrs. Carter astonished her white neighbors by such acts as regularly acting as a nurse to the family's black farmhands and occasionally receiving black visitors in her parlor.

"I've always had a feeling for the underdog, right or wrong," she once said. Her own liberal positions on racial issues influenced those of her son, she asserted.

"Yes, Jimmy got that from me," she said in a 1976 interview. "I've always been like that . . . . I grew up trying to be compassionate and kind to everyone . . . . I've stood alone in Plains; Jimmy and I have stood alone."

Not even serious matters of morality were completely safe, however, from her mischievous sense of humor. In 1976 her son stumped the nation promising that he would never lie.

Mrs. Carter freely confessed to occasional fibs. "I have to make up for Jimmy," she explained.

Bessie Lillian Gordy Carter was born Aug. 15, 1898 in Richland, in southwest Georgia, where her father was the local postmaster. Active himself in politics and public life, her father, James Jackson (Jim Jack) Gordy, was credited with originating the idea of Rural Free Delivery.

After the family moved to nearby Plains, Mrs. Carter defied parental objections to study nursing. She completed her training in Atlanta before her 1924 marriage to James Earl Carter Sr., manager of the Plains farm supply store.

While bearing and raising four children, Mrs. Carter continued to work as a nurse and also took an active part in local politics and church and community affairs. Her husband, then in the peanut business, was elected to the state legislature, but died of cancer in 1953 during his first term.

Mrs. Carter described herself later as first bitter then bored. She became housemother for a time at a fraternity house at Auburn University in Alabama. Later, she managed a nursing home in Georgia.

In 1964 she cochaired the Sumter County campaign for the election of President Johnson, becoming the target of taunts because of Johnson's liberal racial attitudes.

Two years later, when she was 67 and her son was making his first run for the Georgia governorship, she took at face value a televised public service advertisement which said "age is no barrier" to service in the Peace Corps. In December 1966 she left for India where she worked in a family planning clinic, cared for lepers, sought to improve sanitary conditions, and overcame bouts of homesickness and despondency.

The stay she said "meant more to me than any other one thing in my life. It strengthened my faith in God and my relationship with minorities. Whether I did anything for the Indian people, they did so much for me."

On her return, she stumped her state for her son's successful 1970 gubernatorial candidacy, and then in 1976, saw her son nominated for president.

"I had such a feeling of awe that I wanted to weep," she said.

Although she would constantly greet visitors to Plains ("Hello, I'm Jimmy's mama") during the '76 campaign, her main role was to take care of her granddaughter Amy, then 8.

When her son became president, she spent much of her time at home in Plains, but he sent her abroad to represent the United States at the funerals of several foreign leaders.

A voracious reader who was also a fan of soap opera and baseball, she realized a lifelong dream when she threw out the first ball at the fourth game of the 1977 World Series.

Mrs. Carter's death was the second in the family in recent weeks. Her daughter, Ruth Carter Stapleton, died last month of pancreatic cancer.

Mrs. Carter's survivors include 16 grandchildren and eight great-grandchildren.