Field Dodder

Host: Mainly the cultivated species of Trifolium, Medicago, Ziziphus, Alhagi, Tamarix and Acacia species.

This species is closely related to Cuscuta europaea from which it can be separated by its capitate stigma, capsule not circumscissile with a definite line of cleavage, and also by its inflexed petals.

Stems thin, green when young, branched,. intermingled, brown. Leaves minute, scarious, 1-1.5 x c. 0.5 mm. Flowers in compact clusters, each with 2-8 flowers, 2-3 mm long; pedicel glandular, 1-2.5 nun long; bract cup-shaped, brown, 1-2 x 0.5-0.7 mm or sometimes obsolete: Calyx lobes 5, 1.2-1.5 x 1-1.7 mm, fleshy, oval to orbicular, obtuse, glandular, usually with reticulate venation, ± glossy, covering more than half of corolla, tube lobes c. 0.7 mm long. Corolla lobes 1-1.5 x 0.7-1.2 mm, light brown to yellow, oblong-elliptical, acute-obtuse, inflexed, with reticulate venation, lower half usually glossy, upper half mostly non-glossy, tube c. 1 mm long; scarious, slightly bigger than the corolla tube, abundantly fringed. Stamens 5, filament broader at the base, tapering towerds the apex, 0.3-0.7 mm long, fused part of the filament not prominent in the petals; anther oblong-elliptical to oval, c. 0.5 x 0.2-0.3 mm. ovary globular, fleshy, brown, 1-1.2 mm long; styles 2, linear, reddish-brown, 0.5-1 mm long; stigma rounded or capitate, brown, c. 0.2 mm long, and wide; ovule 4, reddish-brown, triangular or ovoid, c. 0.5 x c. 0.3 mm. Capsule depressed-globose, membranous; with a intrastylar opening with glands, 2-2.5 mm long, and broad, not definitely circumscissile, surmounted by sepal lobes, petals and stamens. Seeds 4, reddish-brown, ovoid or somewhat triangular, usually flattened, on one side, 1-1.5 x c. 1 mm; hilum short oblong, usually with small dark circular area around it.

Stems yellowish green to yellow or orange, 0.5-0.8 mm in diam., smooth. Inflorescences lateral, usually compact globular clusters, 4-18-flowered, subsessile. Pedicel ca. 1 mm. Calyx cupular, enclosing corolla tube, ca. 1.5 mm; sepals 5, oval or circular, sometimes wider than long. Corolla white, short campanulate, ca. 2.5 mm, 4- or 5-lobed; lobes broadly triangular, apex acute or obtuse, often reflexed. Stamens shorter to longer than corolla lobes; anthers ovate, shorter than filaments; scales distinct, ovate, ca. as long as corolla tube, fimbrillate. Ovary globose. Styles 2; stigma globose. Capsule depressed globose, ca. 3 mm in diam., ca. 2 mm high, with withered corolla at base, irregularly opening. Seeds 1-4, often 3 or 4, dull yellow, ovoid. 2n = 56.

Distribution: Native to United States; now almost cosmopolitan.

On Allium fistulosum Linnaeus. Fujian (Fuzhou Shi), Xinjiang [Africa, Asia, Australia, Europe, North America, Pacific Islands, South America].

Cuscuta arvensis Beyrich ex Engelmann; C. arvensis var. calycina Engelmann; C. pentagona Engelmann var. calycina Engelmann; C. pentagona var. subulata Yuncker.