AbstractFour new sesquiterpenoids, 1,4‐trans‐6‐hydroxyisocalamenene; 1,4‐trans‐6‐methoxyisocalamenene; (+)‐aristol‐9‐en‐ 12β‐ol, and eudesm‐4(15)‐en‐6β‐acetoxy‐7β‐ol, were isolated from Bazzania tridens, a liverwort species. Their structures were identified by means of spectroscopic methods. The two isocalamenenes are derived from a methyl rearrangement of the calamenene skeleton.