Stems: tufted, slender, weak, climbing or trailing. Leaves: pinnate, tendril-bearing, nearly sessile; leaflets eighteen to twenty-four, linear, obtuse, mucronate; peduncles axillary. Flowers: in spike-like dense racemes, reflexed. Not indigenous.
A lovely climbing or trailing Vetch, with dense spike-like racemes or deep purple-blue flowers and quantities of delicate foliage; the leaves, which are pinnately divided into numerous tiny leaflets, having thread-like tendrils at their tips.
Vicia americana, or American Vetch, has the same nearly sessile pinnate leaves and slender weak stems as the preceding species. It also climbs and trails over every bush and shrub in its vicinity, clinging to them by means of its tiny tendrils; but it differs entirely from V, Cracca in its flowers, which are larger, more mauve in hue, and grow in a scanty, very loose fashion, as opposed to the dense spike-like racemes of the Cow Vetch.
To see the mountain woods blued by these two graceful plants recalls Emerson's reference to how "The million-handed Painter pours Opal hues and purple dye " out upon the flowers of the forest.
The Astragalus, Oxytropis, Hedysarum, and Vicia all belong to the Pea Family, and therefore their flowers are all papilionaceous; that is to say, they have irregular butterfly-shaped blossoms.