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DescriptionThis native vine is a summer annual about 2-6' long that branches occasionally. Its slender stems can climb by twining about adjacent vegetation; they are finely pubescent. Alternate trifoliate leaves occur at intervals along the stems. Each leaflet is about 1" long and 1/3" across; it is oblong-lanceolate, smooth along the margins, and finely pubescent on both the upper and lower sides. Each trifoliate leaf has a long petiole about 1-2" long that is also finely pubescent; there is a pair of small lanceolate bracts at the base of each petiole. No tendrils are produced by this vine. At the base of the middle to upper leaves, a slender flowering stalk (peduncle) about 1-4" long is occasionally produced. Each stalk terminates in a dense cluster of 1-6 small flowers; usually only one flower in a cluster is in bloom at a time. Each flower is up to ¼" long; it has a pale pink to purplish pink corolla. This corolla has a typical pea-like structure that consists of a standard, keel, and enclosing wings. However, the narrow keel and its wings are somewhat unusual in that they curve upward in front of the standard, instead of remaining straight. This characteristic distinguishes the Strophostyles genus from many other members of the Bean family. The short tubular calyx of each flower is light green to purple and finely pubescent; it has 4-5 shallow teeth along its rim and a pair of small bracts (bracteoles) at its base. The pedicel of each flower is very short. The blooming period occurs from late summer into the fall and lasts about 1-2 months. Each flower is short-lived and lacks any noticeable floral scent. A fertile flower is replaced by a cylindrical seedpod about 1–1½" long that has a beaked outer tip. This seedpod is initially green, but becomes dark brown with maturity; it is finely pubescent to conspicuously hairy. Each seedpod contains a few large seeds that are oblongoid in shape; they become dark, shiny, and hairless with maturity. The root system consists of a taproot. This vine spreads by reseeding itself.