AUGUSTA (AP) — John Richardson said Monday he is dropping out of the race for the governor, acknowledging that he failed to qualify for public campaign funding because of irregularities in the way his campaign workers sought donations from voters.

 Citing “disappointing developments,” the Democrat said he would not challenge state election regulators’ decision to deny him campaign funding and said he never considered the option of traditional fundraising for his campaign. Richardson is a former House speaker and economic development commissioner.

 His departure leaves four others — Pat McGowan, Libby Mitchell, Steve Rowe and Rosa Scarcelli — in the Democratic primary race. Seven Republicans are seeking their party’s nomination, and several independents are seeking to get on the general election ballot.

 Even though Richardson has withdrawn, his name will appear on the June 8 Democratic ballot because ballots have already been printed and distributed. The state may encourage towns to post notices that Richardson is no longer a candidate, Secretary of State Matthew Dunlap said. His votes will not be counted.

 Richardson is one of the four candidates who sought public campaign funding through Maine’s Clean Election Act, which provides campaign funding as long as candidates refrain from accepting private donations. Instead, it sets forth a rigorous process in which gubernatorial candidates must collect at least 3,250 qualifying donations of $5 each along with $40,000 in startup “seed money.”

 Speaking at a news conference in his hometown of Brunswick, Richardson said the state Commission on Governmental Ethics and Election Practices found his campaign’s seed money contributions to be in order, but had found problems with the $5 qualifying contributions.

 In a weekend letter to Richardson, the commission said it determined that the candidate’s campaign workers “falsely stated that they collected qualifying contributions” and that the campaign submitted documents “containing material false statements.”

 Commission Executive Director Jonathan Wayne said Monday that during its review of Richardson’s submissions, the commission staff found 39 voters who said they had been contacted by the campaign and signed documents that they had contributed but had not made the $5 contributions.

 The commission staff also found that at least four Richardson campaign workers signed forms saying they had received contributions when they knew the contributions had not been made. The staff found no indication that Richardson or his campaign manager knew of those irregularities, Wayne said.

 Richardson said every one of his campaign volunteers were given specific instructions on how to collect contributions legally. He said he reported his own campaign to the commission when he discovered the irregularities.

 “I did that because I knew we had to maintain the integrity of the system. I did that because I knew I had no choice. That sometimes the process is more important than your own personal ambitions,” said Richardson, who paused at times to regain his composure.

 Richardson said that although his workers “cut corners on the forms they submitted,” he was accountable, “and I accept the responsibility for those mistakes as the candidate.”

 Because he is not appealing the commission staff’s finding, its ruling will stand. The state attorney general’s office assisted in the ethics commission’s review, but it was not clear whether it will pursue a criminal investigation. The attorney general’s office declined to comment.

 Richardson’s decision prompted one of his former Democratic rivals, Rosa Scarcelli, to issue a statement calling for an investigation by an independent outside counsel so lingering questions about the matter can be answered. Scarcelli is raising funds privately.