gigantea (giant vetch), is native to western North America from Alaska to northern California, where it occurs in coastal and moist inland habitat and disturbed areas.

[1] This vetch is a perennial herb with stout, hollow, and ridged climbing stems that may reach two meters in length.

[2] The leaves are made up of 9 to 13 pairs of lance-shaped or elongated oval leaflets that may measure up to 4 centimeters in length.

[2] The inflorescence is a one-sided raceme of up to 15 or 20 flowers which have pale pink to dark reddish purple or sometimes yellowish to orange corollas.

They yield fruits which are legume pods measuring up to 4 centimeters long by 1.5 wide.