This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Pisum maritimum L. Sp. PL 727. 1753.
Lathyrus maritimus Bigel. Fl. Bost. Ed. 2, 268. 1824.
Perennial, glabrous or nearly so, stout, somewhat fleshy, slightly glaucous; stems angled, decumbent, 1°-2° long. Stipules broad foliaceous, ovate, hastate, acute, 1'-2' long; leaves nearly sessile; leaflets 3-6 pairs, oblong, oval or obovate, obtusish and mucronulate at the apex, mainly narrowed at the base, somewhat larger than the stipules; tendrils branched; peduncles somewhat shorter than the leaves; flowers 6-10, 9"-12" long, purple; calyx-teeth often ciliate; pod sessile, linear-oblong, nearly glabrous, veined, 1 1/2'-3' long, 4"-5" wide Sea-beaches, New Jersey to arctic America, shores of the Great Lakes, Oneida Lake and on the Pacific Coast. Also in northern Europe and Asia. May-Aug. Sometimes blooming again late in autumn. Also called sea-side everlasting pea.
Finely pubescent or glabrous, perennial, ascending, climbing or decumbent, 2°-3° long. Stems strongly 4-angled; stipules lanceolate, half-sagittate, acute or acuminate, 4"-12" long, much smaller than the leaflets; leaves petioled; leaflets 4-7 pairs, ovate or oval, obtuse or acutish and mucronulate at the apex, mostly rounded at the base, l'-2' long; tendrils branched; peduncles shorter than the leaves; flowers purple, 6"-8" long; calyx pubescent or glabrous; pod linear, sessile, glabrous, veined, 1 1/2'-3' long, about 3" wide.
River shores and banks, western New Jersey and Pennsylvania to Ontario, Indiana, Saskatchewan, Georgia, Louisiana and Arkansas. Ascends to 3500 feet in Virginia. Leaflets often strongly reticulated. May-July.
Lathyrus palustris L. Sp. Pl. 733. 1753.
L. palustris linear if olius Ser in DC. Prodr. 2: 371. 1825.
Perennial, glabrous or somewhat pubescent; stems angled and usually winged, slender, 1°-3° long; stipules half-sagittate, lanceolate, linear or ovate-lanceolate, 5"-10" long, 1 1/2"-2 1/2" wide; leaflets 2-4 pairs, lanceolate, oblong, linear or linear-oblong, acute or obtusish and mucronate at the apex, narrowed or rounded at the base, 1'-2 1/2 long, 2"-s" wide; tendrils branched; peduncles generally about equalling the leaves, 2-8-flowered; flowers purple, 5"-/" long; pod linear, sessile, slightly pubescent, or glabrous, 1 1/2'-2 1/2' long, about 3" wide.
In moist or wet grounds, Newfoundland to Alaska, Massachusetts, New York, South Dakota and British Columbia. Also in Europe and Asia. May-Aug.