Reproductive biology of a North American subalpine plant: Corydalis caseana A. Gray ssp. brandegei (S. Watson) G. B. Ownbey: REPRODUCTIVE BIOLOGY OF CORYDALIS

Corydalis caseana ssp. brandegei (Fumariaceae) is a perennial plant that grows in moist, subalpine regions of south central Colorado, USA. Prior to this study, nothing was known of its reproductive biology. The most numerous visitors (59%), and the only known pollinators, were long-tongued bumblebees (Bombus appositus). Twenty-nine percent of visits were from short-tongued nectar-robbing bumblebees (Bombus occidentalis). Hum- mingbirds also visited the flowers but they did not pollinate them. Corydalis caseana flowers remained open and in good condition for approximately 4 days. During that time, in the absence of visitors, nectar containing 35% sugar accumulated at a rate of approxi- mately 1 mL per day. Corydalis caseana has a mixed-mating system. It is self-fertile, but the self-fertilized flowers produce fewer seeds per fruit than the outcrossed flowers (a mean of 2.9 compared with a mean of 4.7). Results suggest a possibility of inbreeding depression.