California may be going to pot — literally.

Marijuana would be grown and sold openly to adults 21 and older under legislation introduced Monday morning by a San Francisco lawmaker.

Assemblyman Tom Ammiano, D-San Francisco, said the cash-starved state could generate more than a billion dollars by taxing pot growers and sellers.

Ammiano predicted that the public would support loosening marijuana laws that require substantial public funds to enforce.

"I think there's a mentality throughout the state and the country that this isn't the highest priority," he said. "And that maybe we should start to reassess."

Before California could legalize marijuana, however, it also might have to persuade the federal government to alter its prohibition on cannabis.

Ammiano said federal officials may be receptive to such changes under the administration of President Barack Obama.

"We may be on a parallel track here," said Ammiano, a freshman legislator who was sworn into office less than three months ago.

The Drug Policy Alliance, an advocate of loosening marijuana laws, applauded Ammiano's proposal.

"Marijuana already plays a huge role in the California economy," said Stephen Gutwillig, the group's California state director. "It's a revenue opportunity we literally can't afford to ignore any longer."

Assemblyman Roger Niello, R-Fair Oaks, said legalizing marijuana would be a bad idea. He said he considers pot a "gateway drug" from which many users graduate to harder and more dangerous substances.

"I don't think we're particularly well-served in our society to further accommodate or even encourage something that's going to be unproductive and damaging to the individual — especially not for the reason of generating revenue," he said.

Ammiano's bill, Assembly Bill 390, would allow marijuana to be sold openly — like alcohol — in retail outlets statewide.

The state would gain by charging sellers a fee of $50 per ounce. Pot growers also would be charged under the measure.

Driving under the influence of marijuana would continue to be illegal.

AB390 calls for numerous restrictions, such as banning use near schools or growing cannabis in public view, according to Ammiano aides.

Besides generating new tax revenue, Ammiano said his bill would save money by easing pressure on law enforcement and prisons.

"People in general are supportive," he said.

Ammiano said he hopes that legalizing pot could be a step toward avoiding shortfalls as large as the recent $40 billion projection that prompted months of partisan fighting and, ultimately, tense all-night sessions before agreement was reached on a budget.

"After being locked up with my colleagues for three days, I never want to do that again," Ammiano said, chuckling.