Desmodium sessilifolium (M. Curtis) Torr. & A. Gray (sessileleaf tick trefoil)

Pl. 395 f, g; Map 1748

Stems 50–120 cm long, usually stiffly erect, occasionally slightly arched, often unbranched, the median portion with dense, hooked hairs. Petioles all 1–3 mm long. Stipules 4–7 mm long, 0.5–0.8 mm wide, lanceolate to linear-lanceolate, tapered to a sharply pointed tip, at maturity brown and appressed to spreading, shed early or more commonly semipersistent. Leaflets flat to somewhat folded longitudinally, the undersurface with hooked and straight, spreading hairs, the network of raised veins relatively conspicuous. Central leaflet 3–6 cm long, 0.4–1.5 cm wide (4–10 times as long as wide), narrowly oblong to narrowly lanceolate or narrowly elliptic, the tip mostly bluntly pointed, sometimes with a minute sharp extension of the midvein at the very tip. Lateral leaflets 2–5 cm long, 0.3–1.1 cm wide. Stipels 1–2 mm long. Inflorescences terminal, branched or unbranched, the axis with dense, hooked hairs. Primary bracts 2–5 mm long, ovate, tapered to a sharply pointed tip, semipersistent or shed early. Secondary bracts 1.0–1.5 mm long, linear to hairlike, shed early. Flower stalks 1–4 mm long. Calyces green, with moderate to dense, short, spreading hairs and dense, minute hairs, the tube 1.0–1.5 mm long, the lobes 1.5–3.0 mm long. Corollas 4–6 mm long, pale pink or white, fading to a pale yellowish color, the nectar guides inconspicuous, pale green narrowly outlined in pink. Fruits arched downward in outline, the stalklike base 1–2 mm long, consisting of 1–3(4) segments, each 4–6 mm long and 3–4 mm wide, broadly rounded on the upper margin, rounded on the lower margin, with deeper indentations below, uniformly covered with hooked hairs on the margins and faces. 2n=22. June–September.

Scattered nearly throughout the state, but apparently absent from most of the western half of the Glaciated Plains Division (eastern U.S. west to Nebraska and Texas; Canada). Upland prairies, sand prairies, glades, tops of bluffs, savannas, and sand savannas; also old fields, fencerows, railroads, and roadsides.