The previous erroneous assignment of the structure of columbianin as a D‐glucoside of columbianetin has been revised to indicate that it is a β‐D‐gentiobioside. The mass spectral characteristics of columbianin, its acetate, the true β‐D‐gluco‐pyranoside of columbianetin, and its acetate have been examined and probable fragmentation pathways proposed. Copyright © 1968 Wiley‐Liss, Inc., A Wiley Company