Sida spinosa L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Branching annual 3–6 dm, commonly with a short spine-like process at the base of each lf; lvs petiolate, 2–4 cm, crenate, lance-ovate to oblong or elliptic, basally subtruncate to subcordate; fls fascicled in the axils; pedicels 2–12 mm, the longer ones jointed near or above the middle; cal thinly stellate; pet pale yellow, 4–6 mm, carpels 5, each tipped with 2 erect, hispidulous beaks; 2n=14, 28. Fields, roadsides, and waste places; pantropical, extending n. occasionally as far as Mass. and Mich. July–Oct.