At one Colorado location, Castilleja sulphurea (Scrophulariaceae) is a root parasite on Lupinus argenteus subsp. rubricaulis (Fabaceae). The new carbinolamide quinolizidine alkaloids 2(S),9(R)-dihydroxyaphyllidine (1), 2(R),9(R)-dihydroxyaphyllidine (2), 2(R)-hydroxyaphyllidine or (-)-argyrolobine (4), and 2(S)-hydroxyaphyllidine (5), as well as the known (+)-aphyllidine (6), were isolated from both plant species. The alkaloids are inherent to Lupinus and are transferred to Castilleja via root parasitism. Pairs 1-2 and 4-5 are interconvertible epimers, though they can be isolated pure or as ester derivatives. NMR and X-ray crystal data reveal that each of the four carbinolamides (or their ester derivatives) adopts a conformation where the functional group is perpendicular to the plane of the conjugated amide bond system. Subspecies of the L. argenteus complex differ in quinolizidine alkaloid patterns due to varying timing of ring oxidation steps. Species of Castilleja from the western US were reported to contain pyrrolizidine or quinolizidine alkaloids, which were previously shown to be transferred from host plants via root parasitism. Preliminary evidence indicated quinolizidine alkaloids in a Colorado C. sulphurea population came from L. argenteus subsp. rubricaulis. Here, we report structural and chemical studies on these alkaloids: two have unprecedented combinations of functional groups present individually or partially in other quinolizidines. The alkaloids were isolated as diastereomer mixtures with epimeric carbinolamide groups. We also isolated and characterized (-)-argyrolobine (whose enantiomorph was known but incompletely characterized), which occurred as interconvertible epimers. The presumed biosynthetic precursor (+)-aphyllidine was isolated and spectrally characterized in detail.