- Name also: Bird-in-a-bush, Fumewort
- Family: Poppy Family – Papaveraceae
(formerly Fumitory Family – Fumariaceae)
- Growing form: Perennial herb. Tuberous.
- Height: 10–20 cm. Stem erect.
- Flower: Corolla irregular (zygomorphic), purple–red (sometimes white), 15–20 mm (0.6–0.8 in.) long. Petals 4, of which two inner petals partly united, uppermost petal spurred, spur 9–11 mm (0.36–0.44 in.) long. Sepals 2, soon falling. Stamens 6 in 2 groups, each with 1 whole and 2 half stamens. Gynoecium composed of 2 fused carpels. Inflorescence a 10–20-flowered raceme, subtending bracts large, usually lobed at tip, obovate.
- Leaves: Alternate, stalked. Lowest stem leaf scaly, other 2–3 leaves usually biternate, secondary leaflets sometimes with entire margins, usually lobed.
- Fruit: Resembling a siliqua, quite lanceolate, flat, 10–25 mm (0.4–1 in.) long capsule.
- Habitat: Shore-side broad-leaved forests, stream and river banks, hedgerows at the bottom of precipices, parks. Also an ornamental and escape from cultivation.
- Flowering time: (April–)May.
Genus Corydalis plants resemble hyacinth when they bloom, and they push their way up into the light in the early summer at the same time as the skylarks return. People in olden times noticed this, as can be seen from its Finnish name. Solid-tubered corydalis blooms when skylarks lay their eggs, but it is able to ripen its seeds before the chicks leave the nest. It is pollinated by anthophora plumipes bees, which uncover the stamen when they sit down on the flower’s outermost lower petals and squash the inner petals that surround the stamens and pistil downwards to reveal the stigma. The pollen falls as a ball from the stamens onto the stigma, where it waits for an insect to visit – like many of its relatives, solid-tubered corydalis is self-sterile so pollination does not occur. When a bee pushes its proboscis into the flower to suck the nectar from the back of the spur, the pollen on the stigma sticks to its fur, and is thus ferried to the next flower. Solid-tubered corydalis is often visited by the yellow, black and white white-tailed bumblebee, which steals the plant’s nectar by simply biting a hole in the spur.
Solid-tubered corydalis usually develops a number of seed capsules. The seeds are spread by ants and sometimes they travel in waves if people transplant the whole plant to their gardens as an ornamental. New solid-tubered corydalis shoots develop a single cotyledon, although as a species it is a dicotyledon. The plant only blooms for a short time in the spring, frantically devouring its underground food store, and then withers away.
In Finland solid-tubered corydalis is the most common flower in its genus. It is known for its over-10-flowered raceme, whose subtending bracts are tipped with webbed lobes. Its close relative corydalis intermedia (C. intermedia) is rare and has a maximum of eight flowers, and its subtending bracts are entire.