Madeira-vine

Boussingaultia cordifolia Tenore, Ann. Sci. Nat., Bot., sér. 3, 19: 355. 1853; B. gracilis Miers

Stems twining to 5 m, often producing single or clustered axillary tubers. Leaves: petiole 6-12 mm; blade ovate to orbicular, 2-10 × 1-7 cm, base of larger leaf blades proximal to inflorescences cordate, base of small distal leaf blades tapering, apex obtuse to acute. Inflorescences racemes or in branched panicles of racemes, 10-35(-60) cm; single bract subtending each pedicel triangular-lanceolate, 1-2 × 0.3-0.4 mm; paired bracts subtending each flower persistent, triangular to obtuse, 0.6-1 × 0.5-0.6 mm, basally connate into cup. Flowers bisexual, usually functionally staminate; sepals basally adnate to petals, cream-white, not winged in fruit, ovate to elliptic, 1.2-2.3 × 1.1-2 mm, apex obtuse; petals basally connate, cream-white, ovate to elliptic, 2.1-3 × 1.4-2 mm, apex obtuse, spreading at anthesis; stamens fleshy; filaments basally connate and dilated, 1.9-3.5 mm; anthers early deciduous, 0.7-0.9 mm; pistils 0.4-0.6 mm; styles 1-1.5 mm, basally connate for ¹/2-²/3 their length; stigmas clavate to capitate; pedicel 1-3 mm. Utricles rarely producing viable seeds, style bases persistent, globose, 0.8-1.1 mm. 2n = 24.

Flowering late summer-fall. Disturbed areas, fencerows, roadsides; 0-500 m; introduced; Calif., Fla., La., Tex.; Mexico; West Indies; Central America; Eurasia; Africa; Pacific Islands; Australia; native to South America.

Anredera cordifolia is sometimes cultivated as an ornamental, and it escapes and naturalizes in subtropical to subtemperate regions (C. R. Sperling 1987). In many floristic treatments, it has been confused with A. baselloides (Kunth) Baillon, a species restricted to Ecuador and Peru. Fruit- and seed-set are rare in cultivated material; tubers are the main means by which Madeira- vine is propagated (C. R. Sperling 1987).