According to The Gothamist, and the NYPL's own own tumblr account, Keith Richards visit to the NY Public Library included some 'backstage' time in the Cullman Center's Deputy Director Marie d’Origny's office. This is what went on:
While Keef was waiting in the center before his talk at the library, he unexpectedly lit up a cigarette in Marie’s office, and grabbed the clay saucer underneath a potted orchid for a makeshift ash tray. He then asked for the window to be open, sending a chill through the office. Between the cold and the smoke, the little orchid never stood a chance. RIP, sweet flower. The good news is Keith felt sort of bad about smoking in the first place and signed the “ash tray” without anyone asking (see image). So c’mon - you have to have sympathy for the devil.