7. Calystegia occidentalis (A. Gray) Brummitt, Ann. Missouri Bot. Gard. 52: 214. 1965.
[E W]
Convolvulus occidentalis A. Gray, Proc. Amer. Acad. Arts 11: 89. 1876
Perennials or subshrubs, rootstock woody. Herbage usually puberulent or pubescent, sometimes glabrescent, rarely tomentellous or ± villous. Stems decumbent, procumbent, or twining-climbing, to 400 cm. Leaves: blade ± triangular, 15–40 mm, base usually lobed, lobes rounded or 1–2-pointed, basal sinus quadrate, rounded and ± parallel-sided, or V-shaped, base sometimes ± cuneate. Bracts (1–)3–12(–15) mm distant from sepals, lanceolate, linear, linear-oblong, oblanceolate, or narrowly to broadly triangular, 4–22(–30) × 1–4(–7) mm, margins entire or proximally lobed or toothed. Flowers: sepals 9–15 mm; corolla white or cream, (20–)25–48 mm.
Subspecies 2 (2 in the flora): w United States.
Subspecies occidentalis and subsp. fulcrata are distinguished essentially by entire versus proximally lobed or toothed bract margins; the distinction is not absolute.
