E-Flora BC: Electronic Atlas of the Flora of British Columbia

Lathyrus palustris L.
marsh peavine (marsh pea)
Fabaceae (Pea family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #4103)

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Distribution of Lathyrus palustris
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Species Information

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Perennial herb from a slender rhizome; stems flanged or winged, climbing, 30-100 cm tall.
Alternate, pinnately compound with 4 to 8 paired or scattered leaflets; leaflets linear to oblong-lanceolate or lance-elliptic, glabrous or hairy, 2-7 cm long, 0.3-2 cm wide; tendrils well developed, usually branched and grasping; stipules lanceolate, at most 1/2 the length of the leaflets, usually 2-lobed.
Inflorescence a loose, stalked, axillary cluster of 2 to 8 pea-like flowers; corollas pink to bluish-purple (rarely white), 12-22 mm long, the banner-claw shorter than the blade, the wings and keel nearly equal to the banner; calyces 8-12 mm long, glabrous to hairy, the upper teeth triangular and shorter than the lanceolate lower teeth.
Pods, 3-6 cm long, 4-6 mm wide, short-hairy or becoming glabrous; seeds 5 to 8.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Tidal marshes and mudflats, moist meadows, beaches, streambanks and lakeshores in the lowland zone; infrequent, scattered in coastal BC; N to AK and S to N CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Lathyrus palustris

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 0 1 5
Slope Gradient (%) 0 0 2
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
5 5 7
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: CWH(15)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Lathyrus myrtifolius Muhl. ex Willd.
Lathyrus palustris subsp. pilosus (Cham.) Hultén
Lathyrus palustris var. linearifolius Ser.
Lathyrus palustris var. macranthus (T.G. White) Fernald
Lathyrus palustris var. meridionalis Butters & H. St. John
Lathyrus palustris var. myrtifolius (Muhl. ex Willd.) A. Gray
Lathyrus palustris var. pilosus (Cham.) Ledeb.
Lathyrus palustris var. retusus Fernald & H. St. John
Orobus myrtifolius Alef.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References