Herbs perennial, from rhizome, glabrous or pubescent. Stems narrowly to broadly winged, sprawling or climbing, basally branched 0–4 times, 2–10 dm. Leaves 1–6 cm; tendrils well developed; stipules ovate-lanceolate to linear, 5–25 × 1–10 mm, much smaller than leaflets; leaflets 4–8, paired, blades lanceolate to linear, 15–75 × 2–20 mm, surfaces glabrous, glabrate, or pubescent. Inflorescences 2–7-flowered, 3–15 cm. Flowers 10–15 mm; calyx lobes unequal, lateral lobes deltate, shorter than tube; corolla blue-purple, banner erect, blade equal to claw, wings equal to keel; ovary glandular-pubescent. Legumes 25–60 × 4–8 mm. 2n = 14.

Phenology: Flowering Apr–Aug.
Habitat: Coastal and inland wetlands.
Elevation: 0–1800 m.

Distribution

• Generated Map
• Legacy Map

St. Pierre and Miquelon, B.C., Man., N.B., Nfld. and Labr., N.S., Nunavut, Ont., P.E.I., Que., Sask., Ala., Alaska, Ark., Calif., Colo., Conn., Del., D.C., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., R.I., S.Dak., Tenn., Vt., Va., Wash., W.Va., Wis.

Discussion

Morphological variation within Lathyrus palustris is extensive. Although the most distinctive forms (see synonyms) have been accorded formal nomenclatural recognition (M. L. Fernald 1911; C. L. Hitchcock 1952), intergradation among these mostly sympatric ecotypes is widespread (D. Isely 1998). In Nunavut, it is known only from Akimiski Island in James Bay.

Selected References

None.

Lower Taxa

None.