Taxonomy: Kingdom - Plantae (plants). Subkingdom - Tracheobionta (vascular plants). Superdivision - Spermatophyta (seed plants). Division - Magnoliophyta (flowering plants). Class - Magnoliopsida (dicotyledons). Subclass - Rosidae. Order - Fabales. Family - Fabaceae (pea family). Genus - Vicia L. (vetch) Species -Vicia americana ex Willd.
Ecology: American vetch grows in a wide variety of habitats. It is found in moist to dry areas, swampy woods and borders, mixed forests, and clearings. It is common in moist or sheltered foothill canyons and meadows. American vetch is a nitrogen fixer and has a strong drought tolerance. It may be useful revegetating open or depleted quaking aspen (Populus tremuloides) game rangelands in Utah, including burned over or thinned conifer areas. It is also useful for revegetating coal-mined lands, roadsides, and in critical-site stabilization.
American vetch provides excellent forage for livestock and wildlife. Mule deer, black bear, and grizzly bear browse the leaves and flowers. American vetch also provides forage for game birds and small mammals.
American vetch occurs in all stages of succession. It grows in open sunny sites and invades fire-disturbed areas. It is also shade tolerant. It is found in the understories of quaking aspen communities of the upper Great Lakes region and in Engelmann spruce (Picea engelmannii) communities of the Rocky Mountains. Some common forb associates of American vetch include western yarrow (Achillea millefolium), alpine aster (Aster foliaceus), Virginia strawberry (Fragaria virginiana), wildwhite geranium (Geranium richardsonii), sticky geranium (G. viscosissimum), Canada violet (Viola canadensis), western sagebrush (Artemisia campestris), goldenrod (Solidago spp.), western snowberry (Symphoricarpos occidentalis), and sedges (Carex spp.) (FEIS).