Purple Prairie Clover has compound leaves consisting of 3-5 narrow, linear leaflets. These leaflets measure approximately 0.5 to 1.5 inches (1.3 to 3.8 cm) in length and about 1/8 inch (0.3 cm) in width. The leaflets are slender, elongated, and finely textured, contributing to an airy appearance. Their green hue and simple vein pattern provide a delicate, yet resilient character, making the leaves visually distinctive and easy to identify among other flora.

The flowers of purple Prairie Clover are displayed in dense, cone-shaped spikes measuring 1-2 inches (2.5-5 cm) in length. Blooming from early to mid-summer, they start opening at the bottom of the spike and progress upwards. Each tiny purple flower is about 0.1 inches (2.5 mm) across, showcasing 5 vivid purple petals and 5 conspicuous goldish-orange anthers. The sequential blooming and striking color contrast make these flowers particularly distinctive and visually appealing.

The stem of purple Prairie Clover is characterized by wiry, slightly ridged, green structures. These stems are slender and resilient, standing upright and often reaching heights of 1-3 feet (30-90 cm). The texture is firm with subtle ridges, giving a slightly rough feel. Stems exhibit a moderate degree of branching, primarily near the upper sections, contributing to the plant's bushy appearance. This distinctive stem structure aids in the identification of purple Prairie Clover in its native habitats.

The fruit of purple Prairie Clover is a small legume encapsulating 1-2 seeds. The external pod is initially yellowish-green, maturing to brown, which provides an indicator of the seed's ripeness. Each pod is typically elongated and may exhibit a slight curvature. The size of the seeds is consistent, nestled within the pod that protects them until dispersal. Their texture moves from somewhat soft to firmer as they mature. The legumes are relatively easy to handle, with a size convenient for examination without magnification.