Billy Al Bengston, whose extraordinary watercolors go on view today at the Corcoran Gallery of Art, ought to be a movie. He is lithe, tanned and good-looking, casual yet cunning. If you were to film the most Californian of California's masters, he'd be just right for the part.

Like so many other Californians, Bengston's story opens somewhere else. He was born in Dodge City, Kan. He left there at 14, true, but what could be a better hometown for a painter who would soon be known, until he tired of its toxic fumes, as the surest spray gun in the West?

Though he uses little brushes now, and frequently paints flowers, young Bengston in the '60s was a mucho macho guy. You could film him on his dirt bike, with crowds and motors screaming, for he used to be a professional racer, until one day in the '60s, at Ascot Park, Gardena, he crashed and broke his back. You could show him on the beach, too, with bright sun and bikinis and green walls of water rising, for he used to be a surfer, too, though he's given up on that.

But he has not lost his daring or his balance. His new, near-perfect watercolors prove what has been long suspected: Bengston is, at 46, one of the most lyrical and graceful abstract painters now alive.

That is, if you dare call these works abstractions. None was done from life; none is truly figurative; and most of them include floating squares and arcs. But though these sunny perfumed pictures, with their strict geometries and stenciled iris-emblems, are in many ways abstract, they are also portraits -- not of person but of place.

They were painted in the tropics, in Venice, Calif., in Honolulu and Lahaina -- and their place of making shows.

Bengston paints the sunlight, its brightness and its heat, and its glistenings in seawater. Often he refers to the look of whitewashed walls, "summoning," in the words of the Corcoran's Jane Livingston, who organized his show, "the erotic evocation of light through Venetian blinds." There are breezes in these paintings, tropic nights and blossoms, rainbows, bamboo, palms.

But they're the opposite of postcards. "I'm an abstract painter," Bengston says, "I've always been. Hell, I'm an abstract expressionist." But his works are free of anguish, and none of them is messy. His mastery of watercolor, that most demanding medium, is as close to flawless as anyone could wish.

One of Bengston's pictures, painted in Lahaina, suggests a handful of fresh petals, purple, red and gold, that he has somehow sprinkled on the circle of the moon. Packed into this painting are squares, splatterings and circles, the shadows cast by fronds and the rough trunk of a palm. Somehow it suggests not just the glare of beach-light but the darkness of the night. In the newest pictures here, done last year, the liquid drifts of color that have, until now, lent softness to his shows are cut by bolts of color as earthquakes cut the crust, as lightning cuts the night.

An undertone of menace twitches in these pictures; their paradise is not entirely secure. Bengston was a rebel once, and may be again. It is as if his love of beauty, the seduction of pure painting, has postponed attack. "With hindsight," writes Livingston, whose admirable catalog essay accompanies the show, "it is not so difficult to see that Bengston actually never was destined to become anything but a basically 'conservative' artist, concerned with values of decorative/formal tension in the long modernist tradition."

His art has always had an edge. The sweetly colored "dentos" that he showed here at the Corcoran's Dupont Center in 1969 -- they were made with lacquer sprayed on sheets of dented metal -- were among the purest and the most malevolent abstract evocations of the Southern California mood this city had yet seen. The black and opalescent canvases he displayed at the Corcoran's 1973 Biennial ran off with the show. For 20 years or so, Bengston has had a sort of trademark-emblem: an iris seen in silhouette, a kind of bloom with claws. Inexplicable, romantic, at once flip and belligerent, it glowed within his pictures as a badge might on black leather. He employes it still.

Perhaps it's not surprising that Southern California, once famous for its outlaws, is now known for its tories. The artists of the newest lands may need to conserve most. Bengston's dark blue jacket is cut of British wool, his bow-tie bears white polka-dots. Stenciled amid irises on his green silk handkerchief is the pure painter's war-cry: "Less Duchamp. More Cezanne."

A memory of Brando, lolling in black leather, threatening and haughty, was apparent in his "dentos." Behind the luscious paintings here, some of which have been cut-out and collaged, one feels, instead, the pleasure-giving, endlessly inventive spirt of Matisse.

The Bengston show, one in the series "Modern Painters at the Corcoran," was supported by a grant from the SCM Corp. It closes March 29.