western columbine

Aquilegia formosa is a perennial herb that grows to 20–80 cm in height, averaging around 60 cm. Flowers, which can be seen from April to August (with some variation between regions), are about 5 cm long and red and yellow in color. The sepals and petal spurs are typically a reddish-orange color, attributed to the anthocyanin pigments pelargonidin and cyanidin, and carotenoids. Petal blades are yellow, pigmented by carotenoids. The primary pollinators are hummingbirds, although bees, butterflies, and flies will also visit flowers. Despite several floral adaptations to hummingbird pollination, at ~9,000-10,000 feet in elevation in the eastern drainages of the central Sierra Nevada mountains of California, A. formosa forms hybrid zones with Aquilegia pubescens, which is primarily pollinated by hawk moths. The flowers are edible, with a sweet taste—though the seeds can be fatal if eaten, and most parts of the plant contain cyanogenic glycosides.

Within its range, the crimson columbine can be found in most kinds of habitat (chaparral, oak woodland, mixed-evergreen or coniferous forest). It is not found on desert floors, nor at altitudes above 3300 metres, and it is absent from the Central Valley of California. It prefers moist locations such as stream banks.

Aquilegia is derived from the Latin word 'aquila', meaning 'eagle', or possibly from the Medieval German words 'Acheleia' or 'Akelei'; this name is in reference to its talon-like nectaries. Formosa means 'handsome', 'beautiful', or 'well-formed'.