Alkaloid levels in Duncecap (Delphinium occidentale) and Tall larkspur (D-barbeyi) grown in reciprocal gardens: separating genetic from environmentalinfluences

The objective of this study was to determine whether differences in toxicit y between Tall larkspur (Delphinium barbeyi) and Duncecap larkspur (D. occi dentale) were genetically inherent within the species, or due to environmen tal influences unique to the different regions where they grow. There was n o difference in the concentration of the toxic alkaloids between the two sp ecies when grown in common gardens. However, both species had higher concen tration of toxic alkaloids when grown in the southern Rocky Mountain region which is characterized by summer monsoonal thunderstorms, compared to summ er drought in the north. In a unique occurrence where Duncecap larkspur gre w beside Tall larkspur, toxic alkaloids were very low in Duncecap larkspur, but total alkaloid concentration was often higher than in Tail larkspur. P ublished by Elsevier Science Ltd.