Corydalis (kor RI dal is) from the Greek word korydalis meaning crested lark.
Corydalis is a genus with finely divided fern like foliage and four-petaled irregular flowers with spurs that appear to resemble the those of the lark. The genus consists of about 470 species of both annuals and herbaceous perennials, and is native to Europe, Asia , and the mountains of tropical eastern Africa. It is a member of the poppy family Papaveraceae and closely related to bleeding heart, Dutchman’s breeches, and squirrel corn. Most species do will in semi-shade, consistently moist, well-drained soil. Few species are available and only one, Corydalis lutea, is common in the US.
Here are three examples of garden worthy Cordalis species.
Sūrat C. lutea
Also called yellow fumitory, this perennial is the mostly commonly grown Corydalis in the US but is native to the foothills of the southern Alps in Switzerland, Italy, and Yugoslavia where it grows on shady rocks and screes. The golden yellow flowers are ¾ inches long and carried in dense elongated racemes over a long bloom time beginning in May . The three to four times pinnate foliage is distinctly three-lobed and forms a neat mound. The plant spreads easily by seed and may pop up in unexpected places.
Color: Golden yellow
Hardiness: Zone 5-7
http://shinyfastandloud.com/?feed=rss2 C. flexuosa
Commonly known as blue corydalis, this rhizomatous perennial is native to China where it grows on steep shady slopes and flowers in April and July. The blue flowers have long spurs and are carried in dense racemes on slender stems. The racemes have up to ten flowers and may be up to three inches long. Each flower is one inch long and has a whitish throat. The leaves are finely divided and up to six inches long. Plants do not like the heat and may go dormant during the summer sometimes reappearing in the fall to bloom again. They are also known for their finicky nature and may disappear entirely for no apparent reason. Well known cultivars are “Blue Panda’ and ‘Pere David’
Hardiness: Zones 5-8
Native to moist shady areas of northern Europe and Asia, this spring ephemeral has a tuberous root system and dies down after blooming. The mauve, purple, red, or white flowers are up to one inch long and carried in clusters of up to twenty in spring. The foliage is medium green, deeply divided, and fernlike.
Color: Mauve, red, purple, white
Hardiness: Zones 4-8