Flora of North America species comparison

Dicentra cucullaria is occasionally confused with D. canadensis, with which it is sympatric. It is distinguished from that species by its basally pointed (versus rounded) outer petal spurs, by its flowers lacking a fragrance, by flowering 7-10 days earlier, and by its pink to white, teardrop-shaped (versus yellow, pea-shaped) bulblets.

After fruit set, the bulblets of both Dicentra cucullaria and D. canadensis remain dormant until fall, when stored starch is converted to sugar. At this time also, flower buds and leaf primordia are produced below ground; these then remain dormant until spring (P. G. Risser and G. Cottam 1968; B. J. Kieckhefer 1964; K. R. Stern 1961). Pollination of both species is effected by bumblebees (Bombus spp.) and other long-tongued insects (L. W. Macior 1970, 1978; K. R. Stern 1961).

Flavonoid components indicate that Dicentra canadensis and D. cucullaria are more closely related to each other than to any other member of the genus (D. Fahselt 1971). Even so, species purported to be hybrids between them probably are not. There is considerable variation in floral morphology within D. cucullaria, which can have flowers superficially resembling those of D. canadensis. However, when all characters of the plants are examined, these putative hybrids almost always are clearly assignable to one species or the other.

The western populations of Dicentra cucullaria appear to have been separated from the eastern ones for at least a thousand years. The western plants are generally somewhat coarser, which apparently led Rydberg to designate the western populations as a separate species. Plants from the Blue Ridge Mountains of Virginia, however, are virtually indistinguishable from those of the West, and much of the variation (which is considerable) within the species probably involves phenotypic response to the environment, or represents ecotypes within the species.

The Iroquois prepared infusions from the roots of Dicentra cucullaria for a medicinal liniment (D. E. Moerman 1986).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 20 (9 in the flora).

About 35 isoquinoline alkaloids have been isolated from Fumariaceae, and such compounds are present in the tissues of all species. Some of these alkaloids have been used medicinally, mostly in the past. The drug complex corydalis, which contains several alkaloids extracted from the bulblets of Dicentra canadensis and D. cucullaria, has been used as a healing agent in chronic skin diseases, as a tonic and diuretic, and in the treatment of syphilis. The alkaloid bulbocapnine, obtained from all parts of D. canadensis, has been used in the treatment of Ménière's disease and muscular tremors, and as a pre-anaesthetic. Cattle find D. cucullaria and D. canadensis distasteful and usually do not ingest the plants unless suitable forage is unavailable; when they do, however, the toxic alkaloid cucullarine brings about local anaesthesia, narcosis, convulsions, and death. A decoction from the rhizome of D. formosa has been used in the Pacific Northwest to expel intestinal worms (D. E. Moerman 1986).

Dicentra spectabilis (Linnaeus) Lemaire is cultivated through much of the flora area. It was introduced in Europe only in the middle of the 19th century, but it has been cultivated for centuries in temperate China and Japan, where it is now so widespread that the limits of its natural distribution are obscure. It does not appear to be truly naturalized in North America, but it may be encountered as a transitory garden relict or escape. It differs from D. ochroleuca and D. chrysantha in having rose-purple to pink or sometimes white outer petals, pendent flowers, and reticulate seeds with elaiosomes.

(Discussion copyrighted by Flora of North America; reprinted with permission.)