Calystegia macounii
Ann. Missouri Bot. Gard. 52: 215. 1963.
Perennials, rhizomatous. Herbage puberulent. Stems usually ascending-decumbent, sometimes proximally erect, distally weakly twining-climbing, to 50–70 cm. Leaves: blade deltate, ovate, ovate-hastate, or ovate-lanceolate, 20–60 × 15–50 mm, base lobed, lobes ± rhombic, rounded, basal sinus rounded, apex rounded to subacute. Bracts immediately subtending sepals, oval, ovate, or ovate-oblong, (12–)15–21(–27) × (8–)10–16(–20) mm, proximally flat or slightly saccate, apex usually obtuse, sometimes acute. Flowers: sepals elliptic to ovate, 12–16 mm; corolla white, (35–)40–52(–69) mm.
Phenology: Flowering May–Aug.
Habitat: Grassy sites, including tall grass and mixed grass prairies, prairie slopes, disturbed sites, meadows, openings in woodlands, stream banks.
Elevation: 400–2200 m.
Distribution
Alta., Man., Sask., Ariz., Colo., Idaho, Iowa, Kans., Ky., Minn., Mo., Mont., Nebr., N.Mex., N.Dak., Okla., S.Dak., Tex., Utah, Wyo.
Discussion
Calystegia macounii is morphologically and geographically intermediate between C. catesbeiana and C. malacophylla and between C. malacophylla and C. spithamaea. It differs from C. sepium in habit and leaf shape; in the Great Plains area, it is most readily identifiable by its hairy herbage, C. sepium there being glabrous.
Selected References
None.