Cuscuta polygonorum smartweed dodder Cuscutaceae CUPO; Q, a; 

Cuscuta polygonorum.John

Cuscuta polygonorum.John (Accessed 7/2014).

Cuscuta polygonorum is a parasitic annual herb, orange-stemmed vine, closely entwining host plant and entering host by numerous haustoria; vines strongly phototrophic, climbing only upward and counterclockwise, forming tangled masses at top of host stem, seedling root system degenerates when haustorial connection to host formed. 

Leaves none or scale-like, alternate. 

Flowers white, 4-parted, 0.2 cm, petal lobes triangular, tips pointed, calyx lobes as long or longer than petal tube, tips very blunt; inflorescences of small, dense clusters. 

Fruit dry, hollow capsule, whitish, rounded, cupped by withered flower parts, 0.2 x 0.3 cm, persistent into winter, massed at tops of host stems; seeds 2-4, about 0.1 cm. 

Wetland status: NL. 

Frequency in NYC: Rare (NYS S1, E). 

Origin: Native. 

Habitat: In open areas on other herbs, occasionally on shrubs. 

Notes: May kill host. Listed as a noxious weed by the USDA (USDA 2004).