1. Alcea rosea Linnaeus, Sp. Pl. 2: 687. 1753.
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Common hollyhock, rose trémière Common hollyhock, rose trémière
Alcea ficifolia Linnaeus; A. glabrata Alefeld; Althaea ficifolia (Linnaeus) Cavanilles; A. mexicana Kunze; A. rosea (Linnaeus) Cavanilles; A. rosea var. sinensis (Cavanilles) S. Y. Hu; A. sinensis Cavanilles
Plants 1–2.5+ m, roughly stellate-hairy to hirsute. Leaves: stipules ovate, 8 mm, apically 3-lobed; petiole equaling or longer than blade; blade suborbiculate to 5–7-angled or shallowly triangular-lobed, sometimes more deeply channeled and winged dorsally, 6–8 mm. Seeds tuberculate or not, often minutely hairy. 2n = 42.
Flowering May–Oct; fruiting Jun–Oct. Disturbed sites, roadsides, vacant lots; 0–3000 m; introduced; N.B., Ont., Que.; Ariz., Calif., Colo., Conn., Del., D.C., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Oreg., Pa., R.I., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Asia (China); introduced also nearly worldwide.
Alcea rosea is a showy and popular ornamental that is essentially cosmopolitan in cultivation. The species is thought to have originated in the southwestern provinces of China but is apparently not known in the wild. It occasionally escapes and naturalizes in disturbed temperate areas nearly worldwide. However, it is often difficult to determine if a given specimen was cultivated or an established adventive. Plants with more deeply lobed leaves and rose-pink flowers have been called A. ficifolia; plants in cultivation under this name are most likely a mix of A. rosea and A. rugosa or of hybrid origin.