Although buds in a crystal bowl decorate the reception room of Lear's Magazine on Park Avenue, they're not the editor in chief's favorites.

Frances Lear prefers full-blown flowers that have known the sun, the wind, the rain. The white-haired editor is convinced there's a certain beauty only experience and maturity can bring.And the magazine she founded last February for the woman who wasn't born yesterday celebrates her concept.

The celebration of the older woman is long past due, she says.

Over the years, our American culture has come to worship the budding beauty, the ingenue with the unlined face. Mature women all too often have been relegated to the background and made to feel like unfortunate "has-beens."

Perhaps in Granny's time such an attitude could be, in part, forgiven. But these days, middle age no longer is something to dread or deny. Proper diet, exercise, beauty products and cosmetic surgery have made attractiveness virtually a lifelong proposition. Modern medical care has made it possible for women to enjoy health and vigor well into their middle years and beyond.

Today 46 million females in the United States are over the age of 40. By the end of the next decade there will be 64 million. And, if you take into account what they're accomplishing . . . well, how could that term "has-beens" apply?

Glamorous, sophisticated, conscious of fashion but certainly not its slaves, women of a certain age are making their mark in virtually every facet of our society.

Consider some who've been featured in Lear's so far: a self-made millionaire in Manhattan who runs one of the city's most successful advertising agencies; a pioneering black woman automobile dealer in Detroit; a divorced mother of two who founded the first overnight shelter for females in Washington, D.C.; a dancer who had the courage to leave a career she loved and begin a new life at 57; a television anchor who feels she's just hitting her stride at 50 - and they're representative of thousands more.

Older women these days, stresses the magazine editor, aren't sitting home counting the gray hairs. They're intelligent, involved, educated, committed - and if they don't like the gray, they're doing something about it! They're ideal role models for younger women and can serve as an inspiration to us all.

Even though over-40 females never have been more vocal or visible, they haven't received much attention from the media, according to Lear. Very little television focuses on them; very few movies. Advertising seems to always seek out the dewy, fresh face. And when it comes to magazines - well, pick up almost any of the leading fashion and beauty publications today, she says, and you'll see models who are about 15 wearing those designer clothes. The older person seldom, if ever, is featured. And the same thing applies to most of the articles. They're youth-oriented, glorifying the teenage rock star; the actress who's just 20; the young executive on the rise.

"I wanted reading material that applied to a woman my age; something that addressed my needs and concerns," she explains. "I hunted. I kept track over the years. Frankly, the void was distressing. My friends kept complaining about it, too. Every time we'd get together, I'd hear them talking about it.

"Finally, I decided to do something about the situation and founded a magazine directed toward the older market, even though I recognized there were great risks involved and I had no experience in the publishing field."

Some told her the enterprise was doomed from the start. They questioned the appeal of older women as cover girls; they questioned the wisdom of the editorial slant - wouldn't features glorifying the mature state grow stale after awhile?

Finding qualified employees who were willing to leave good jobs and gamble on a new enterprise was tough, too. But Lear was determined to give it a try. And so far the rapid increase in circulation (around 200,000 nationwide) plus brisk newsstand sales seem to have justified her actions.

"The reception we've received has been wonderful," she says, sitting in her Manhattan office that's staffed to a large extent by vibrant older women such as veteran fashion editor and one-time model China Machado.

"Everywhere I go, everybody I meet seems to have something complimentary to say about what we're doing. They also ask: `Why didn't anybody think of it before?' Well, I can't answer that, but I do know several people in publishing who are planning to enter the market in the near future - there are other magazines for the older woman presently in the works. I'm proud that we initiated this movement. I can honestly say I've never been involved in a project that has been more personally rewarding or challenging."

The challenge came at an opportune time in Frances Lear's life. Married for several decades to Norman Lear, the noted writer, producer and director, she recently suffered through a divorce. It was a painful period, she admits; a time when it was necessary to either find a new direction or become the victim of self-pity.

With characteristic tenacity, Lear, who's the mother of two daughters, made the positive choice and launched a career in publishing.

Her magazine, concerned with the needs and lifestyles of older women, wasn't a complete departure from past interests. A native of upstate New York, she attended Sarah Lawrence College and studied retail merchandising at New York University. In the late '60s, she founded Women's Place Inc., a Los Angeles consulting firm for women that engaged in government fund work projects. When the urgent need for qualified women in industry became apparent, Lear established Lear Purvis Walker & Co., the first executive search firm in America specializing in the placement of female executives.

She has written and lectured extensively on women's issues, and her articles have appeared in such leading publications as the New York Times, the Washington Post, the Los Angeles Times, the Harvard Business Review, Vogue, Newsweek, the Nation and the Wall Street Journal.

Her activities also have included politics - in the 1984 presidential elections she served as a partner in a consulting firm and founded a division for female candidates. And she served as the principal fund raiser for a national voter registration effort for women during the same election year.

"I've never had trouble keeping busy," says the small, dynamic woman with a smile. "I've never had much time to worry about getting older, either. I will admit that there are things that happen to us as we age that are reminders of our mortality - things that can be disconcerting. But the best way of coping, I'm convinced, is to keep active and involved and to constantly seek out new projects.

"Life isn't easy for anyone. Husbands sometimes leave us; children grow up and are gone; many of our dreams are dashed into bits and pieces. The positive thing is: adversity and change don't have to do us in. By keeping our minds active, by reaching out to others, by having positive attitudes and truly believing in ourselves, we can rise above almost anything."

Believing in ourselves. Lear says that's crucial to being happy at any point in life. And so is the development of a healthy ego.

All of us deserve the right to develop our talents and to become involved in projects or work that make us feel like people of worth, emphasizes the editor. The word "ego" should be placed alongside toothbrushes and pasted above wall switches and taped on computer terminals. Having healthy self-esteem isn't the same as being self-centered.

Her own sense of self-esteem has grown greatly since the magazine was introduced. Lear isn't afraid to say so, and she isn't afraid to call herself a late bloomer.

"Like hundreds of other women in this world today, I feel like I'm just coming into my own," she explains. "Every new day excites me. I want to keep editing this magazine, of course. But more than that, I want to be a spokesperson for women over 40 and send out the message:

"We're here. We're strong. And you're going to be hearing a lot from us!"