19. Calystegia silvatica (Kitaibel) Grisebach, Spic. Fl. Rumel. 2: 74. 1844. (as sylvatica).
[F]
Convolvulus silvaticus Kitaibel, Neues J. Bot. 1: 163. 1805
Perennials, rhizomatous. Herbage glabrous. Stems twining-climbing. Leaves: blade ± cordate, to 50–120 mm, base rounded or lobed, lobes rounded or 1-pointed, basal sinus ± quadrate to rounded. Bracts immediately subtending sepals, lanceolate, to 30 × 15–35 mm, proximally saccate, margins strongly enfolding sepals, apex obtuse to truncate. Flowers: sepals oval to ovate, 15–23 mm; corolla white, sometimes pinkish-striped, rarely otherwise pink-tinged, 43–70[–88] mm; stamens 23–40 mm; anthers 4–6.5 mm.
Subspecies 3 (2 in the flora): North America, Europe, Asia, Pacific Islands (New Zealand); temperate regions.
Subspecies silvatica is native to eastern Mediterranean Europe; it has corollas (50–)55–75(–88) mm, stamens (25–)28–36(–39) mm, and bract apices emarginate to truncate.
Intermediates between Calystegia silvatica and C. sepium may be due to ancient or recent hybridization.