Grocers are calling it "green gold."

Johnny Carson jokes that the Arabs have given up oil - they're planting romaine instead. Salad-bar owners are tossing in their sleep. Standing in the check-out line at a local supermarket, a female employe is heard to say that although she had been ringing up heads of iceberg lettuce for 99 cents each all day, the cost didn't register until she went shopping herself. "I won't pay that much for lettuce," she tells a line of sympathetic customers.

Because of recent heavy rains (eight to 10 inches) in the Salinas area - the Salad Bowl of California - this month's lettuce crop was virtually washed away. "The country gets 80 percent of its lettuce from that area," said USDA economist Charles Porter. "The normal supply is approximately 1,300 truckloads a week. As of last week, "I don't think they even shipped 300 truckloads." And the ones that did survive were soggy, smaller-than-usual heads caked with mud.

But Porter says the shortage is temporary. A spokesman from Salinas siad it hadn't rained since mid-April so there should be a plentiful supply of lettuce by the end of the month iwth prices back to normal.

Last week in New York, iceberg lettuce was selling for over $1.35 per head. In Washington supermarkets, the price was 99 cents, which met with some resistance. Safeway reports that lettuce sales have declined by as much s one-third. "Sales have decreased," said spokesman Ernie Moore, "but we hear the new cropis coming in shortly."

Why should retailers reduce the price if consumers are willing to pay? "I do think people get conditioned to paying higher prices," Charles Porter says," but in my house you'll never condition me to lettuce at 99 cents a head."

Consumers can boycott lettuce, buy more spinach or cabbage or just go salad-less. Restaurants cannot. "They're really taking a beating," says Porter, the hardest hit being the all-you-can eat salad bars and vegetarian establishments.

"We're hanging in there," says Frank Sarris, owner of The Orleans House in Arlington, home of the "Riverboat" salad bar. Sarris is currently paying $24.95 for a case (24 heads) of iceberg lettuce. Two weeks ago the price was between $5 and $7 per case. "Its unreal," Sarris says.

Though most area restaurants were trying to absord the loss, hoping that prices will go down by the end of the month, several eateries have already translated the shortage into higher prices on the menu.

The cost of all salads at the vegetatian Gate Soup Kitchen in Georgetown has been raised 10 to 20 percent. "My produce dealer tells me that by this summer," says manager Roger Johnson, "even after this crisis is over, the price of lettuce will be $1 to $2 more per case than last summer.Then there's the labor. The lettuce we've been getting is so caked with mud we have to spend more time and trouble cleaning it."

Jerry Cosker, purchasing manager for the six are Sir Walter Raleigh Inns, is concerned that prices may have to go up. "One of the main attractions here is the salad bar. We're in the same boat as every restaurant in the country. But produce is like a yo-yo. Lettuce is up, but peppers and cucumbers are down," says Cosker. Has salad become as costly as the sizzling steak that goes with it? According to Cosker, "There's no question about it."

At the Golden Temple, prices are going up by 10 percent. "But the lettuce is no worse than the cauliflower," said one spokesman. "Cauliflower and broccoli prices are sky high. In fact, it's all the vegetables from California."

Emersons' restaurant will wait out the week before making any decision. They've been tosssing around a few ideas, having already increased the proportion of escarole and romaine to the once-dominant iceberg. "We're trying to hold the price down, but if it doesn't break soon we're contemplating a 50 cents surcharge on the salad bar as a last resort," says vice president Jim Miller.

Will customers balk? "That's what worries us to death."