<jats:title>Abstract</jats:title><jats:p>The alkaloids 1′,2′‐didehydrostemofoline (<jats:bold>2</jats:bold>) and 2′‐hydroxystemofoline (<jats:bold>3</jats:bold>) from <jats:italic>Stemona collinsae</jats:italic> <jats:sc>Craib</jats:sc> (Stemonaceae) were studied by X‐ray crystallography and NMR spectroscopy, and they are compared with the parent compound stemofoline (<jats:bold>1</jats:bold>). The X‐ray analysis of the CH<jats:sub>2</jats:sub>Cl<jats:sub>2</jats:sub> solvate of 2′‐hydroxystemofoline (<jats:bold>3</jats:bold>) allowed the determination of the absolute configuration of this compound unequivocally, whereas optical rotation was used to infer the absolute configuration of 1′,2′‐didehydrostemofoline (<jats:bold>2</jats:bold>). Based on these results, it is shown that asparagamine A isolated from <jats:italic>Asparagus racemosus</jats:italic> <jats:sc>Willd.</jats:sc> (Asparagaceae) is identical to 1′,2′‐didehydrostemofoline obtained from <jats:italic>S. collinsae</jats:italic> <jats:sc>Craib</jats:sc>, and that the reported plant source of asparagamine A was most likely a <jats:italic>Stemona</jats:italic> species. In the context of the current investigations, a novel concept on the biosynthesis of <jats:italic>Stemona</jats:italic> alkaloids has been worked out and is presented here.