3. Cuscuta L. (dodder, love vine)

(Yuncker, 1943)

Plants parasitic on the aboveground portions of other plants. Stems twining, glabrous, greenish yellow, yellow, or orange, often forming tangled mats and attaching to host tissues by suckerlike haustoria. Leaves alternate, consisting of small, lanceolate or ovate, sessile scales 1–4 mm long. Inflorescences sessile or stalked clusters along stems, sometimes appearing as small panicles. Flowers with the surface smooth or densely and minutely papillose (warty or bumpy), sometimes also with scattered resinous (pellucid-glandular) cells. Calyces 3–5(6)-lobed, sometimes deeply divided to form separate sepals. Corollas white, rarely greenish, 3–5(6)-lobed, the lobes erect to recurved, the tips sometimes incurved. Stamens with a scalelike appendage (infrastaminal scale) attached to the corolla tube below the attachment point of the filament, this infrastaminal scale with a toothed or fringed margin. Ovary 2-locular. Styles 2, each with a capitate (linear elsewhere) stigma. Fruits papery-walled capsules, usually with an aperture between stigmas, breaking open irregularly (with circumscissile dehiscence elsewhere). Seeds usually 2–4 per fruit, brown. About 145 species. Nearly worldwide.

Contrary to some reports, Cuscuta species do produce chlorophyll, although in reduced quantities. Some species of dodder are important agricultural pests and have been spread as contaminants in crop seeds. Species identification in the genus is challenging and requires a hand lens. Details of the flowers are easiest to observe in fresh specimens or in plants that have been dried without pressing. Most dodders parasitize a wide variety of host species, and determination of the host is usually not an aid in Cuscuta identification.