Over the weekend, Umphreys McGee performed two shows at San Franciscos Fillmore Auditorium, inviting saxophonist Mitch Marcus onstage both nights. On Friday, Marcus appeared on Soul Food I and It’s About That Time. A night later he returned to help Umphreys debut on a new song, Intentions Clear. Based in the Bay Area, Marcus is known for leading his own quintet, as well as backing such musicians as Donovan, Stanley, Trevor Dunn’s Convulsant Trio, Good for Cows, Japonize Elephants and Realistic Orchestra. Umphreys McGee will perform Friday at the Green Apple Music Festivals free EarthFair outside Grand Central Station, while Marcus will appear at Berkleys Jupiter.