The family of plants known as Fumariaceae, commonly called the fumewort family, includes almost 600 unique species of herbaceous plant in 20 different genera. One of the largest of these genera is the genus Corydalis, which itself includes 470 unique species. Plants of the genus Corydalis are usually either annuals, or plants that live for only one year or growing season, or perennials, which are longer lived plants that survive for longer than two growing seasons. The plants have spiky flowers in shades ranging from white to yellow to pinkish purple or lavender, and green, fleshy, fan-like leaves. They are sometimes grown in gardens as a decorative ground cover, and some species also have medicinal uses due to the presence of several alkaloid substances in their rhizomes, which are stem structures that grow underground.
Genus Corydalis is native to areas of the Northern hemisphere where the climate is mild and periods of extreme heat or cold are relatively uncommon. It is particularly successful in China, the Himalayas, and in mountainous regions of eastern Africa. However, the plants of this genus are easy to grow and may be cultivated in almost any temperate region.
As garden plants, species of Corydalis make effective ground covers because the plants spread out and propagate themselves quickly, sometimes to the point where gardeners consider the plants to be pests. The plants are usually grown from tubers, or bulbs, but unlike many other tuberous plants, they do not thrive in full sun conditions. Corydalis species tend to prefer moist, rocky soil with very good drainage and conditions of partial shade. For these reasons, the plants make good additions to a rock garden and can also be grown at the base of trees or bushes. Plants of this genus also tend to attract butterflies, bees, and occasionally birds, because the animals consume the plant as food.
The colorful flowers for which the plants are prized are early bloomers, flowering between the spring and early summer months. Different species of Corydalis have flowers of different shades. One of the most common species grown in gardens is C. solida, which has purple flowers and a bluish tinge to its green leaves.
Some species of Corydalis, such as C. cava, contain alkaloids, or chemical compounds high in nitrogen, in their rhizomes. These compounds can be fatal to livestock like cows or sheep who ingest the plant by accident while grazing. The particular alkaloids found in C. cava and other related species act on the muscular system and inhibit the activity of muscles, so they are sometimes used medicinally to treat muscle tremors.