Performer: Joan La Barbara

Now they know how many cacti it takes to fill the Albert Hall. Last night’s marathon John Cage Prom finished up, over three hours after it had started, with a wonderfully cactus-heavy performance of Branches (1976).

Bravo to Michael Tilson Thomas and the San Francisco Symphony for blowing the dust off of some of the boldest innovators America has produced. As part of a mini-festival at Carnegie Hall of 20th- and 21st-century composers who stretched musical and formal boundaries (to put it mildly), the program on Tuesday night was packed with rarely-played wonders.