The plant bears an inflorescence of two to eight pinkish purple pea flowers each up to two centimeters wide.

Lathyrus linifolius is a perennial plant with a sprawling or climbing stem that grows to 25 to 80 cm (10 to 31 in) and is shallowly-winged and nearly hairless.

The leaf blades are pinnate with two to four pairs of narrow lanceolate leaflets, entire margins and a terminal branching tendril.

Its typical habitat is in rich ground and this plant is found in damp meadows, on river banks, on the margins of ponds, by lakes and near the sea, and occasionally in coastal hedgerows.

As the common name implies, Marsh Pea, it is found in wet to moist areas where it can receive adequate sun and also allows other plants to climb on.