Sida Linnaeus (1753: 683).

Lectotype (designated by Britton & Brown 1913: 520):— Sida alnifolia Linnaeus (1753: 684).

Perennial subshrubs or shrubs, erect, prostrate, decumbent or scandent, glabrous or pubescent, with simple, glandular or stellate trichomes. Leaves alternate, petiolate, stipulate, distichous or helicoidal, blades ovate, elliptic, rhombic, linear, lanceolate, suborbicular, narrowly elliptic, narrowly oblong or oblong, usually crenate-serrate or serrate (rarely entire and sometimes entire only at the base), rounded at the base, truncate, cuneate, cordate or subcordate. Solitary flowers, glomerules or umbelliform inflorescences, rarely bracteolate; flowers bisexual, 5-merous, dichlamydeous and heterochlamydeous, epicalyx absent; calyx often 10-ribbed, 10-costate at the base; corolla yellow, pink, salmon, orange, white, sometimes with a red or purple center; petals asymmetric; stamens aggregated at the apex of the staminal tube; styles 5–14. Schizocarps with 5–14 mericarps, indurate, differentiated into two parts: a lower oneseeded, indehiscent (sometimes dehiscent), usually reticulate; an upper, empty, dehiscent, usually smooth, muticous, submuticous or biaristate (rarely with one aristae); seeds solitary, glabrous.