Plants herbaceous or woody at base, perennial, rhizomatous, prostrate or erect to twining. Stems to several meters long. Leaves subsessile to petiolate, oblong to hastate or sagittate, rarely pedate. lobes angular or lobed. Inflorescences axillary, usually 1-flowered, sometimes few-flowered cymes; bracteoles 2, sepal-like, usually inserted immediately below calyces, ovate and sometimes saccate, enclosing calyx, sometimes remote from calyces and subulate or leaf-shaped, persistent. Sepals subequal, persistent; corollas usually white or pink, sometimes pale yellow, funnelform, with 5 distinct midpetaline bands, glabrous; stamens included, equal; pollen globose, pantoporate, not spiny; ovaries with 1 chamber and 4 ovules; styles 1, 2-branched, branches clavate, complanate. Capsules globose, glabrous, indehiscent; seeds 4, smooth or minutely tuberculate, black.
Calystegia is usually treated as having about 25 species but Fang and Brummit (1995) comment that it has about 70 subspecies, all of which intergrade and that they "can be arbitrarily comined into about 25 species". It is primarily a genus of temperate regions.
Austin, D.F. & S. Ghazanfar (1979). Convolvulaceae in E. Nasir & S.I. Ali (Eds.) Flora of Pakistan 126: 6.
Fang, R-C. & R.K. Brummitt. (1995). Convolvulaeaein Wu, Z.Y. and P.H. Raven (Eds.), Flora of China vol.16