Nectar secretion was studied in dandelion growing in a crested wheat-grass field in the Peace River region of Alberta, Canada. The average number of flowers produced daily in an area 1 m2 was 59'2 in 1981 and 8'9 in 1982. Most flowers opened in the morning and closed in the afternoon. Quantity and concentration of nectar were significantly higher in flowers 2 days old than in those 1 day old. Average nectar volume, sugar concentration and sugar value were 7'4 ~dlflower, 55'1% and 5' 2 mglflower/24 h respectively in 1981 and 3'7 ~IVflower, 42'6% and 1'9 mglflower/24 h in 1982. Larger flowers produced more nectar. Nectar-sugar concentration and sugar value increased with increasing temperature. High nectar-foraging activity by honeybees coincided with peak nectar-sugar production.