This article says the Maine Green Party’s gubernatorial candidate, Lynne Williams, will not seek public funding this year. Of course, Green Party candidates for the Maine legislature can be expected to seek and obtain public funding this year.
As the article points out, due to a good change in the election law last year, qualified parties in Maine no longer need to poll 5% of the vote for either Governor or President. Instead, they remain ballot-qualified if they have at least 10,000 registered members who cast a vote in November. The Green Party has over 34,000 registered members so it probably will retain its spot on the ballot, whether it polls 5% for Governor this year or not.