|Dicotyledon|| Literature for Sida spinosa
Lorence & Wagner, 2020.
|Malvaceae -- The Cacao, Linden, Mallow Family||Bibliography|
Common name(s): prickly sida
|Distribution||Origin uncertain, but perhaps native to tropical America. This morphologically variable species is now widely naturalized in tropical and warm temperate regions worldwide.In the Hawaiian Islands, naturalized on Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Hawai`i.|
||Erect annual, perennial herb, or subshrub, 0.3‒0.8 m tall; copiously minutely stellate puberulent, eventually glabrate.
||Leaves petiolate; blade linear to narrowly oblong or ovate, 0.6‒7 cm long, 0.2‒1.7 cm wide, margin serrate to crenate, base obtuse to truncate; petiole usually ½ or less the length of blade, 0.2‒1.8 cm long; stipules filiform, 2‒5 mm long, each subtended by a short tubercle.
||Inflorescences a solitary flower or flowers in clusters, often somewhat corymbose toward the ends of the branches. Flowers on slender pedicel, 0.2‒2.8 cm long; calyx strongly 10-ribbed, 4‒7 mm long; petals pale yellow to yellowish orange, 5‒6(‒7) mm long; staminal column included.
||Fruit with 5 mericarps, 3‒4 mm long, grading apically into 2 antrorsely pubescent awns 0.5‒1.5 mm long, proximal abaxial and lateral walls strongly reticulate, apical surfaces smooth, puberulent.
||Seeds ca. 1.5 mm long, glabrous or with a few hairs around the hilum.
||2n = 14, 28.