Resin Chemistry Grindelic acid is the primary component of the resin in most species of Grindelia in North and South America. It is not yet known how variation in resin chemistry affects physical properties of the resin. Grindelia havardii of Texas and G. discoidea of Argentina produce labdanoids lacking the tetrahydrofuran ring that is characteristic of grindelic acid and its derivatives. Reproductive Biology Grindelia camporum var. Hand pollinations between plants from different populations showed that all populations were fully compatible.
Individual florets remain open for one day.
Anthesis in the capitulum is centrifugal with ray florets opening last. Achenes mature approximately 22 days after pollination and are fully dispersed 53 days after anthesis. Mean achene weight is 430 g-1. Crop Culture Agronomy Grindelia camporum var. Arizona field trials were initiated with transplants since the achenes proved to have a light requirement for germination.