By Sharon Bernstein

SACRAMENTO, Calif. (Reuters) - Supporters of a California ballot initiative to legalize marijuana for recreational use may begin gathering signatures to place it before voters in 2016, a state official said on Monday.

The proposal is the latest of four marijuana-related initiatives vying for a spot on the ballot at a time when many believe the most populous U.S. state is on track to join Colorado, Washington, Alaska and Oregon in legalizing recreational pot.

Legal sale of marijuana for recreational use in Oregon is set to begin on Wednesday.

Proponents of the California initiative approved for circulation on Monday have 180 days to collect 365,880 valid signatures in order to place it on the November 2016 ballot, Secretary of State Alex Padilla said in a news release.

The proposal would impose an $8 per ounce excise tax on dried marijuana and allow cities and counties to impose sales taxes as well. It would also set up procedures for reconsidering the prison sentences of people convicted of marijuana-related offenses.

Other proposed California ballot measures would also legalize recreational use, and one would limit the abilities of cities and counties to regulate medical marijuana dispensaries.

In 2010, a closely watched ballot initiative to legalize recreational pot use failed, but a recent poll by the Public Policy Institute of California showed that 55 percent of likely voters support legalizing marijuana for recreational use.

The use of marijuana for medical purposes has been legal in California for two decades, prompting a boomlet in dispensaries and criticism that prescriptions are too easy to get.











(Reporting by Sharon Bernstein; Editing by Eric Beech)