Dicentra

Herbs, annual or perennial, scapose or caulescent, from taproots, bulblets, tubers, or rhizomes. Stems when present erect, simple or branching, hollow at maturity. Leaves basal or cauline, compound; blade with 2-4 orders of leaflets and lobes, margins entire, crenate, or serrate; surfaces glabrous, sometimes glaucous. Inflorescences axillary, extra-axillary, leaf-opposed, or terminal, unifloral or else multifloral and thyrsoid, paniculate, racemose, or corymbose. Flowers bilaterally symmetric about each of 2 perpendicular planes; sepals caducous; corolla cordate to oblong in outline; petals coherent or connate only basally, not spongy; outer petals both swollen or spurred basally, usually keeled apically; inner petals with blade fiddle-, spoon-, or arrowhead-shaped, claw linear-oblong to oblanceolate; stamens with nectariferous tissue borne on median filament in each bundle and sometimes forming spur or loop that projects into swollen base of adjacent outer petal; ovary broadly ovoid or obovoid to narrowly cylindric; stigma persistent, with 2 lobes or apical horns, sometimes also with 2 lateral papillae. Capsules indehiscent or dehiscent and 2-valved. Seeds few-many, elaiosome usually present. x = 8.

Distribution

Temperate North America and eastern Asia.

Discussion

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.

Selected References

Berg, R. Y. 1969. Adaptation and evolution in Dicentra (Fumariaceae), with special reference to seed, fruit, and dispersal mechanism. Nytt Mag. Bot. 16(1): 49-75.

Fahselt, D. and M. Ownbey. 1968. Chromatographic comparison of Dicentra species and hybrids. Amer. J. Bot. 55: 334-345.

Fahselt, D. 1970. The anthocyanins of Dicentra (Fumariaceae). Canad. J. Bot. 48(1): 49-53.

Stern, K. R. 1961. Revision of Dicentra (Fumariaceae). Brittonia 13(1): 1-57.

Stern, K. R. 1962. The use of pollen morphology in the taxonomy of Dicentra. Amer. J. Bot. 49: 362-368.

Stern, K. R. 1970. Pollen aperture variation and phylogeny in Dicentra. Madroño 20: 354-359.

Stern, K. R. and M. Ownbey. 1971. Hybridization and cytotaxonomy of Dicentra. Amer. J. Bot. 58(9): 861-866.

Lower Taxa

Dicentra canadensis, Dicentra chrysantha, Dicentra cucullaria, Dicentra eximia, Dicentra formosa, Dicentra nevadensis, Dicentra ochroleuca, Dicentra pauciflora, Dicentra uniflora

Key

1	Plants with evident stems, not scapose.	> 2
1	Plants without evident stems, scapose.	> 3
2	Petals dull to yellowish white, 15–30 mm; inflorescences subglobose; seeds ca. 1.3 mm diam. (rarely to 2 mm diam.).	Dicentra ochroleuca
2	Petals golden yellow, 10–22 mm; inflorescences elongate; seeds 1.5–2.2 mm diam.	Dicentra chrysantha
3	Plants with elongate rhizomes; bulblets or tubers absent.	> 4
3	Plants without elongate rhizomes (occasionally with rhizomes in D. pauciflora); short, bulblet- or tuber-bearing rootstock, or cluster of spindle-shaped tubers, or combination of tubers and bulblets present.	> 6
4	Reflexed portions of outer petals 4–8 mm; e United States.	Dicentra eximia
4	Reflexed portions of outer petals 2–5 mm; w North America.	> 5
5	Stamen bundles with median filament essentially connate with others.	Dicentra formosa
5	Stamen bundles with median filament forming distinct angular loop extending outward above base.	Dicentra nevadensis
6	Plants with well-developed bulblets; nectariferous tissue forming spur.	> 7
6	Bulblets absent or minute (less than 1 mm diam.); nectariferous tissue not forming spur.	> 8
7	Bulblets globose, yellow; nectariferous spur 1 mm or less.	Dicentra canadensis
7	Bulblets teardrop-shaped, pink to white; nectariferous spur 1–3(–4.5) mm.	Dicentra cucullaria
8	Flowers 1–3 per inflorescence; non-reflexed portions of outer petals usually 12 mm or more; blades of inner petals narrowly spoon-shaped, never triangular or lanceolate.	Dicentra pauciflora
8	Flowers solitary; non-reflexed portions of outer petals usually less than 7 mm; blades of inner petals triangular to lanceolate or spoon-shaped.	Dicentra uniflora