Jane Gaynor, her gentle face still heart-shaped and her eyes still warm despite the passing of years, seated herself on a sofa yesterday at the Brazilian Chancery, adjusted a pillow to support her diminutive stature, and talked about Mary Martin.

"It's really one of the most special friendships. We've known and depended on each other for so many years that neither of us can even place when we first met. We've been very close, and it had nothing to do with our careers, because they hardly coincided. It comes from those days when were all neighbors in Brazil."

And with that the double doors to the large drawing room flew open and Martin entered, arms raised and head thrown back as if she were about to burst into "I'm as corny as Kansas in August."

"Bom dia, Dona Janete," said the star of "South Pacific," "Peter Pan," and nearly four decades on the Broadway stage without a significan flop.

"Bom Dia, Dona Maria," came the matching Portugese reply from Gaynor, once of the most bankable stars in Hollywood, and whose performance in "Seventh Heaven" in 1928 won her the first Oscar ever awarded to a woman.

The embrace that followed gave every appearance of a reunion of long-lost friends. But the truth was the day before from Palm Springs, where Martin moved several years ago to be close to Gaynor.

Martin placed herself on the sofa. Gaynor attentively handed her a pillow. And the two started on a nonstop dialogue that, if allowed, could have gone on all day.

Martin: "Oh, Janet, I love that coral carving on your necklace. You bought that in Rio didn't you?"

Gaynor: "Your beads are Brazillian too. Don't I recall that you actually watched them being made."

In conversation together they are tender, animated and saucy - with Martin the more mischievious. If the Martin-Merman duo is like the contest of two virtuosos, Martin, 65 and Gaynor, who is in her early 70s, together are like two very affectionate sisters.

It was Gaynor and her late husband, the costume deisgner, Adrian, who encouraged Martin and her husband Richard Halliday, to give up Hollywood and return to the stage, because Martin hated making films.

"Without you we would not have done it," says Martin, patting Gaynor on the arm.

"It was a terrible risk," retorts Gaynor, "and we would have felt awful, with you breaking a contract and all that, if you had not been such a triumph." (The first of the triumphs was "One Touch of Venus" of 1943.)

These days Martin lives alone and Gaynor has married producer Paul Gregory. Since Halliday's death, Martin seems especially to depend on Gaynor for advice.

Martin, for example, was trying to decide recently whether to star in an ABC television film - and was not able to reach Gaynor in time.

Retorts Gaynor, "Mary, I know you. The fact you had to make up your mind fast is the reason you did it. If you had waited several weeks, you would have started thinking of reasons not to."

It is called "Valentine," and Martin plays a 71-year-old woman. "I had to dye my hair white to look older - imagine me having to look older - but then everybody knows my hair is a different color every day anyway. Then I went to Lane Bryant and bought some baggier clothers because I thought they would help."

"When we were filming it - on location - I tried to take your advice, Janet, and look with my eyes into the camera. But most of the time I couldn't even see the camera. I hope that after 34 years, I've finally learned to act in films - a slow study, you might say."

Then modesty overtakes her, and she starts to suggest she may not even watch it.

Gaynor interrupts: "Don't worry, I'll take care of that."

Does Martin regret not being in any of the films made of her musical? "Not one bit."

Gaynor intervenes: "But Mary, none of the films were great successes."

Martin thinks a minute and says, "Well, there was the movie version of 'The Sound of Music.'"

"Well," Gaynor continued, "Otherwise, it was a real loss. But I guess you've got your recordings, such as 'South Pacific.' Just as I've got my films."

What brings them to Washington is a ceremony tonight at which they will receive the Brazilian Legion d'Honneur, which is called the National Order of the Southern Cross; this is for "promoting friendship" between the two countries since establishing their "second homes" there in the early '50s. Coincidentally, an exhibit of Gaynor's bright flower paintings will be on view at the Brazilian-American Cultural Institute through next week.

This is the fifth of Gaynor's art exhibitions, all of which have sold out. The first painting to be sold in her latest group went for $1,600 last night. Called "A Sunburst of Color," it was purchased for the embassy's collection. Earlier exhibitions were in New York, Palm Beach, and twice in Chicago.

But what solidified their friendship was 18 years of escaping to their respective retreats not far from what is now Brasilia. It was Gaynor and her husband who first discovered the spot, called Anapolis, on a trip there in 1950.

"We finally located this little spot on the map. Once we got there, we decided we wanted to stay.

"Adrian designed a large Moorish house that Martin calls "the most beautiful I've ever seen."

Martin continues the story: "Soon after, Richard and I were looking for a break after 'Peter Pan' so we ended up taking a freighter to South America.

"We didn't even know they were in Brazil at the time, but Janet got a clip in the mail about it from Hedda Hopper's column, and when we docked in Santos, Brazil, a lady came to the ship with a letter in her hand asking, "Are you Mary Martin and Richard Halliday?" and she had an invitation from Janet and Adrian.

"We had virtually no time, and we had to go 500 miles each way just to get there. Janet, I remember the furniture was just arriving and we had dinner on the king-sized bed. Then we sat up al night and talked. And as we left Richard pointed to another building and said, 'If that house is ever for sale I want it.'"

The Hallidays had their Brazilian farm within a year. Gaynor recalls, "For much of the time we had nobody to visit except each other. We would send formal invitations to each other and dress for dinner.

"At first there were six gates that had to be opened between the houses - before we put in cattleguards. And, Mary always had to get out to open them.

"And, Mary, do you remember the time it rained when you were coming to our place, and when you got out each time you had to take off that chiffon dress and open the gates in your slip?"

"Janet," Martin retorts, "I'm not even sure it was as much as a slip."

Both still own their Brazilian farms. Martin returns each year, but the last time Gaynor was there was 6 years ago, when she stayed with Martin.

They are asked, now that Martin has returned to the cameras, if they might not do something together.

"Well," replies Martin, "it just happens that I finally got up the nerve to ask that myself on the plane yesterday. But I'm still waiting for an answer."

Gaynor just smiles. For the first time in the conversation she doesn't have a rejoinder. CAPTION: Picture, Mary Martin, left, and Janet Gaynor, by Larry Morris - The Washington Post