Perennials or subshrubs, root­­stock woody. Herbage glab­rescent, glabrous, or ± hairy, including puberulent and/or pubescent. Stems prostrate, weakly trailing, or twining-climbing, to 100 cm, or strongly twining-climbing, to 900+ cm. Leaves: blade linear or broadly to narrowly triangular, to 130 × 1–120 mm, basally lobed, lobes 2–3-pointed or rounded, basal sinus acute, rounded, or ± quadrate. Bracts immediately subtending sepals, lanceolate to ovate or suborbiculate, (6–)8–30(–37) × 4–30 mm, proximally flat, keeled, or saccate. Flowers: sepals 7–25 mm; corolla white or cream, sometimes fading pink to purplish, 22–68 mm.

Distribution

California, n Mexico.

Discussion

Subspecies 6 (6 in the flora).

Selected References

None.

Lower Taxa

Calystegia macrostegia subsp. amplissima, Calystegia macrostegia subsp. arida, Calystegia macrostegia subsp. cyclostegia, Calystegia macrostegia subsp. intermedia, Calystegia macrostegia subsp. macrostegia, Calystegia macrostegia subsp. tenuifolia

Key

1	Bracts 16–30 mm wide, proximally keeled or saccate.	> 2
2	Bracts 13–23(–26); sepals 10–17(–22) mm; corollas 36–55(–60) mm; stamens 17–26 mm.	Calystegia macrostegia subsp. macrostegia
2	Bracts (19–)22–30(–37); sepals 16–25 mm; corollas 47–68 mm; stamens 23–32 mm.	Calystegia macrostegia subsp. amplissima
1	Bracts 4–16 mm wide, proximally flat, keeled, or ± saccate.	> 3
3	Bract apices acuminate, emarginate, or obtuse.	Calystegia macrostegia subsp. cyclostegia
3	Bract apices acute.	> 4
4	Herbage ± grayish pubescent.	Calystegia macrostegia subsp. arida
4	Herbage glabrous or puberulent, usually glabrescent.	> 5
5	Leaf blades broadly to narrowly tri­angular, (7–)12–20(–30) mm wide excluding lobes.	Calystegia macrostegia subsp. intermedia
5	Leaf blades linear to narrowly tri­angular, 1–7 mm wide excluding lobes.	Calystegia macrostegia subsp. tenuifolia