Family dysfunction, once a shameful secret reserved for tight-lipped conversations behind closed doors, has become the stuff of punch lines and self-help books. But back in 1970, when The Effect of Gamma Rays on Man-in-the-Moon Marigolds first debuted off Broadway, the subject remained novel enough to earn playwright Paul Zindel the Pulitzer Prize for his first and most successful effort. The material has mellowed with age, overshadowed by fresher, crazier portrayals of insanity like August: Osage County, but make no mistake — Gamma Rays is still a devastating family portrait.

The Hunsdorfers live in a ramshackle house strewn with rabbit droppings, their windows papered over (to defend against prying eyes? Because the matriarch is an agoraphobe? It’s never quite clear). Withdrawn Tillie (Julia Wilson) tends to her pet rabbit and nurtures marigolds for the school science fair. The seeds, we learn, have been exposed to cobalt-60, a radioactive isotope that produces genetic mutations. Her sister, Ruth (Maka Fouchi), suffered a nervous breakdown in the recent past, but has since recovered enough to attend school regularly, a privilege not afforded Tillie. Their mother, Beatrice (Tracey Williams), meanwhile, stews around the house in a dressing gown, directing caustic comments at her daughters, her absent ex-husband and the elderly woman she boards to make ends meet.

This might sound dismal, and it’s true the play lacks the snappy uplift a sitcom treatment might afford the same subject matter today. The metaphor of the marigolds is one returned to again and again in the Ojai Art Center production, directed by Steve Grumette. It becomes a means of understanding both Beatrice’s relationship to her daughters and the relative hope for their futures: the marigolds closest to the source of radiation, Tillie discovers, wither and die. But those just slightly removed absorb enough radiation to give rise to fantastic variations of stunning beauty and survive.

As Ruth, a narcissist-in-training with some of her mother’s fire, Fouchi acts with her voice rather than her body. Consequently, she sometimes seems to be performing in a silo — an acting technique suggested, but not wholly supported, by her character’s tunnel vision. Likewise, Wilson’s Tillie retreats into a dreamy-eyed stasis, stroking and murmuring to her rabbit, and subsequently her marigolds. Behind a curtain of stringy hair (Tillie struggles with self care), each reaction appears a little delayed, isolated behind a veil of self-protection. With Nancy Solomons as the stone-silent Nanny, that leaves Williams’ Beatrice to carry the play — which she does, spectacularly.

As a toxic perversion of a woman with seemingly boundless vitality and strength, until life beat her down, Williams is chilling and riveting. We discern that Beatrice lives in the house where she grew up, a pointed symbol for the stunting that has depressed and embittered her. She still harbors pretensions to class and civility, as well as hope for the future — maybe she’ll open a tea shop after all. But each dream spoils in her hands, and eventually her joylessness becomes a self-fulfilling prophecy.

Williams wisely lets us glimpse just enough of Beatrice’s radiance to understand who she might have been had circumstances turned out differently. These flashes of warmth and intimacy sear all the more painfully when, inevitably, they fade. Beatrice is far from a happy woman, but as an anatomy of a creature in despair, Williams’ performance nails it.

The Effect of Gamma Rays on Man-in-the-Moon Marigolds through June 16. Ojai Art Center Theater, 113 S. Montgomery St., Ojai. 640-8797 or