North American Mycological Association
Sonoma Mycological Association
SOMA has an excellent camp in late January. www.somamushrooms.org/
Humboldt Bay Mycological Society
Mendocino Fungi Club (based inland)
Bay Area Mycological Association
Mycological Society of San Francisco
Fungus Federation of Santa Cruz
FFSC hosts two forays at JDSF each year. Become a member and join in the fun. http://ffsc.us/