Morella Camejo, left, widow of Green Party co-founder Peter Camejo, chats with former San...

BERKELEY — Hundreds gathered Sunday to honor the memory of Peter Camejo, champion of the Green Party, at the university from which he was expelled years ago.

"Peter was expelled from Berkeley for unauthorized use of a bullhorn," Camejo's former running mate Ralph Nader said, to the laughter and applause of a 400-person crowd in the International House auditorium on the UC Berkeley campus. Nearly 20 of Camejo's friends, family members, collaborators and comrades spoke at the event, including Richmond Mayor Gayle McLaughlin, former San Francisco Supervisor Matt Gonzalez and Camejo's widow, Morella Camejo.

"You've all brought pieces of him with you," Camejo said to the crowd. Then she thanked them, "because I just can't imagine life without Peter. ... He couldn't stop coming up with new ideas. His mind was restless, forever making plans for the future."

Peter Camejo died in September after a second battle with cancer. He led a prominent public life as a major figure in the Green Party, an author and a spokesman for all manner of humanitarian and progressive causes.

Gus Horowitz, a colleague of Camejo's in the Socialist Workers Party, described attending MIT with Camejo 50 years ago, and taking physics class together. After a test one day, Horowitz and several other students stood together puzzling over a particularly difficult problem and consulting the textbook, which explained a complex solution.

"But Peter, it turned out, had completely bypassed the text and solved the problem by a simple appeal to symmetry," Horowitz said, adding that the experience was telling of Camejo's future efforts.