Comprehensive DescriptionRead full entry
DescriptionThis annual wildflower is 1-2½' tall, branching occasionally. It is semi-erect, using its tendrils to cling to adjacent vegetation. The stems are light green, ribbed, and sparsely pubescent. Alternate compound leaves about 3-5" long occur at intervals along each stem; each leaf is even-pinnate with 5-6 pairs of leaflets and a branched tendril at its tip. The petioles of the compound leaves are short. At the base of each petiole, there is a pair of dentate stipules about ¼" in length. Individual leaflets are about ¾" long and ¼" across; they are oblong in shape and smooth along their margins with short pointed tips. Each leaflet has a short petiolule (basal stalklet) about 1 mm. long. at its base. The upper leaflet surface is medium green and hairless, while the lower surface is pale green and slightly pubescent along the central vein. The middle to upper leaves produce 1-2 flowers from their axils; these flowers are nearly sessile (pedicels about 1 mm. long). Individual flowers are about ¾" long, consisting of 5 purple petals and a light green tubular calyx with 5 teeth. The petals are arranged in a pea-like floral structure consisting of a banner, 2 wings, and a keel; the latter encloses the reproductive organs. There is usually a patch of white at the base of the banner (uppermost petal). The teeth of the calyx are linear-lanceolate and similar to each other in length. The blooming period occurs from late spring to mid-summer for about 2 months. The flowers are replaced by elongated seedpods about 1½-3" in length that are hairless. Initially, the seedpods are green and flattened, but they later become dark brown and more swollen as the seeds enlarge. Each seedpod contains 5-12 seeds. Individual seeds are subgloboid (somewhat flattened) and smooth. This wildflower spreads by reseeding itself.