LUCY AND ETHEL. Laverne and Shirley. Mary and Rhoda. Gertrude and Alice. Now add "Sally and Marsha," heroines of a tiresome two-character comedy by Sybille Pearson at the Round House Theater, to the pantheon of female bonding.

Commendable performances by Kathy Yarman as Sally, and Gina Franz as Marsha make a shovelful of saccharine go down in this excursion into the world of refrigerator magnets by the author of the motherhood musical "Baby."

Here Pearson is allowed to run unchecked by musical numbers for nearly 21/2 hours, and her stillborn jokes sound like a collection of Erma Bombeck rejects. Director Gillian Drake dawdles and pads the play with little songs and scraps of business -- it's like a dust kitty that tumbles aimlessly around the room picking up more fuzz.

Naive, nurturing Sally moves from the Midwest to a West Side apartment with her husband, an Amway-type salesman, and several unseen children. One day, she discovers neurotic neighbor Marsha supine in the hallway (she's avoiding her detested mother).

And so this odd couple's friendship inevitably blossoms in eight scenes that correspond to Sally's pregnancy, and they become a coupla white chicks sitting around talking -- about housekeeping, sex, recipes and their personal pain. Marsha leads Sally to read "Little Dorritt" and teaches her how to put an edge on her cheerfulness; and under Sally's sunny tutelage, suspicious Chekhovian Marsha lightens up, has orgasms with her husband, eats organic food and goes back to college.

With her late-'70s sensibility, Pearson pretends to champion simple values. But her words mock Sally's complacency, and she seems more comfortable with Marsha's tart, urbane wisecracks. The dialogue is disconcertingly disconnected, and the playwright's concept of friendship seems to be a mutual regression to infancy, spiced with the occasional tantrum. We measure the growth of Marsha's character by the fact that she "progresses" from wearing severe black to wearing tennis shorts and lavender Benetton sweaters.

Both actresses try hard and have likable moments. As the aggressively girlish Sally, Yarman is a funny performer who grows in appeal, though it seems at first she's actually trying to imitate Sally Struthers. And given a more coherent script, Franz would convince anyone as Manhattanite Marsha.

It's true that little traumas and shared joys cement a friendship, and many a play has been made of such modest stuff. But if we wanted to be bored sitting around a shabby apartment, it wouldn't be hard to find more interesting boring people than "Sally and Marsha."

SALLY AND MARSHA -- At the Round House Theater through February 9.