She has a potato face and a Karl Malden nose. The word "dumpy" was coined to describe her body. And yet, Maureen Stapleton, our perennial prime-time TV widow, makes you realize that big noses, spreading figures, and most important, female late middle age, are fine things after all.

All by herself, Stapleton is challenging the sterotypic notions of beauty, sexuality and aging, no small feat. She has had three spectacular roles in the last few years. In each, she has been a widow with an emerging strong sense of herself, who meets a man who adores her.

The men are very different. They range from a short, fat, married Charles Durning in the "Stardust Ballroom" and the repressed, elegant, separated E. G. Marshall in "Interiors," to the handsome, suave and available Efrem Zimbalist Jr. in "The Gathering, Part II." No matter, they all find in Stapleton what they are looking for, and nobody in the audience has any trouble identifying what the men are so crazy about.

In all the dramas, Stapleton plays a traditional widow, tied to family and cooking, exuding warmth and affection. She is loved by her grown children, although they react with resentment to her new romantic interests. (In "Interiors," it is the lover's children who react angrily; in the others it is Stapleton's.) The plots focus on Stapleton's stuggle to separate her own needs from her children's while remaining a caring mother.

The conflicts in these plays are rarely explored with any depth. No matter, Stapleton is better then her lines. She manages to present a new kind of late middle-aged woman, and in our admiring response to her roles, we realize how misogynous most of the other TV portraits of older women are. w

There are a number of new things that Stapleton does well. To seasoned TV viewers, used to the likes of motherhood as portrayed by Nancy Walker in "Rhoda," Stapleton makes the maternal relationship to adult children look remarkably attractive. She plays an experience, helpful mother and grandmother, who has achieved some wisdom through living.

In "The Gathering, Part II," her sophisticated daughter seeks and receives sensible help around a difficult pregnancy decision; in "Interiors," Stapleton gives strong and tactful support to her new lover's children when tragedy occurs. She never plays the older mother as that figure of derisive fun that we are so used to.

Even more different, Stapleton plays a grandmother in her late 50s and early 60s, who needs love and sensuality, without that need appearing in any way ridiculous. To the contrary, it is in the very combining of the experience mother role with her successful reaching out for a new adult male relationship, that she is most touching and impressive.

It is a sad commentary that these most traditional roles that Stapleton plays seem so strikingly refreshing and different. She does not play women who are interested in "liberating" themselves in the most obvious 1970s way (finding meaningful outside work, getting ahead in the company), but chooses to portray those women whose experiences are most stereotypically female.

Yet, as she plays them, we realize, as many feminists are now proclaiming that there is liberation in acknowledging one's own worth and competence in family relationships, however we may choose to define the elusive concept of "family."

This kind of self-recognition has not usually been protrayed sympathetically by our media. An older worried mother of an adult daughter (as Stapleton plays in "The Gathering, Part II") is usually seen as interfering and difficult, someone whom the younger offspring needs to stand up to in order to be "her own person." Stapleton's dramas remind of that other part of us, the need of connecting.

This is not a culture that equates sensuality with life experience. Our sex goddesses, with rare exceptions, have been under 30. If they are older, they'd better have the cheeckbones and figure of Katherine Hepburn.

I'm not even sure that Stapleton has cheekbones. In contrast to a sleek Hepburn. Stapleton's appeal is that she is able to break through stereotypes, to combine the qualities one associates with a material stance with that of a sensual one. What emerges is a special kind of rich female personality.

Newspapers and TV have been filled with stories about the fact that older people have sexual needs, and act on those needs. We are told that these needs are not to be viewed as cute or quaint, not to be seen as cause for snickering.

No one would dare snicker at Stapleton. She plays parts, it is true, that are sometimes a bit too noble, a little larger than life. But she is teaching us something about combining motherhood, grandmotherhood, and sensuality, with a wisdom and prespective that comes with many decades of rich living.

In a country where older women have to deal with a double predudice, hers is a refreshing portrayal, indeed.