In 1962, we reported the elucidation of the structure and configuration of cyclobuxine-D, a prototype of a new class of steroidal alkaloids from Buxus sempervirens L. containing a cyclopropane ring. Subsequent studies characterized several structurally-related alkaloids. We report here the isolation and characterization of buxenine-G, a new alkaloid from B. sempervirens L. with a conjugated diene system and lacking the cyclopropane ring of previous Buxus alkaloids. Buxenine-G was isolated from the acetone-soluble portion of strong bases via sulfate salt precipitation, oxalate-salt precipitation, and partition chromatography (Phenol Red stationary phase), yielding its isopropylidene-imine derivative (C₂₈H₄₆N₂, m.p. 186-188°C, [α]ᵈ² +51°). Physicochemical characterization (UV, NMR, mass spectrometry, catalytic hydrogenation, Ruschig degradation) revealed a molecular formula of C₂₅H₄₂N₂, containing a heteroannular diene, four carbocyclic rings, four tertiary methyl groups, one secondary methyl group, one N-methyl group, one primary amino group, and no cyclopropane ring. Biogenetic considerations and data (e.g., circular dichroism of salicylaldimine derivative indicating α-configuration of C-20 primary amino group) led to proposed structures VI and VII. Buxenine-G is likely identical to Stauffacher's "nor-buxamine".