Annual parasitic vine over 50 cm long Stem: orange or pinkish yellow, climbing on other plants and attaching to them with specialized outgrowths (haustoria) which invade tissue of the host plant to absorb food. Leaves: alternate, orange or pinkish yellow, very small, scale-like. Flowers: many, obviously stalked, white, small, 2 - 5 mm tall, radially symmetric, widely cylindric with five, erect or ascending, short, pointed petal lobes. The flowers are held on 2 - 7 mm long, slender stalks, and are arranged in relatively large (1.5 - 3 cm diameter), loose (sometimes compact), rounded, stalked clusters scattered along the stem. Sepals: five, but fused at base, then separating into five, broadly triangular, pointed or somewhat blunt-tipped lobes which are shorter than or possibly almost as tall as the petal tube. Petals: five, but fused for most of their length into a wide tube, then separating into five, erect or ascending, short (much shorter than tube), broadly triangular lobes with pointed and slightly incurved tips. The petal tube is usually pimpled and often has visible lengthwise nerves. Stamens: five, attached to inside top of petal tube alternating the petal lobes, with short filaments, but the anthers visible and sometimes extending beyond petal lobes. Pistil: with one, two-chambered, superior ovary; and two, 0.5 - 1.5 mm long styles which end in rounded stigmas. Fruit: small, somewhat rounded, four-seeded, membranous capsules enclosed by persistent withered petal tube. The persistent styles sit on top of the capsule within a depression which is surrounded by an evidently thickened ring or collar.
Similar species: Cuscuta indecora var. neuropetala is probably most similar to C. coryli since that species also has stalked flowers in sometimes loose clusters, and its flower petals are pimpled and the tips curve inward. However, C. coryli has much longer petal lobes (about equal to tube), and more distinguishing, the flowers only have four sepals, four petals, and four stamens. If individuals of C. gronovii have loose and more spaced flower clusters with short-stalked flowers, some could confuse it with C. indecora var. neuropetala, but that species has rounded tips on the sepal and petal lobes, the petal lobes spread laterally, and the fruit is only surrounded at the base by the remnant petal tube. Another species with more loose flower clusters and stalked flowers is C. cuspidata, but it differs by having bracts below each flower, non-fused sepals, and lateral spreading petal lobes.
Flowering: July to September
Habitat and ecology: Rare, supposedly preferring moist areas, especially sandy openings.
Occurence in the Chicago region: native
Notes: The Cuscutaceae family has only one genus, Cuscuta. The family has often been treated as a subfamily of the Convolvulaceae family since their flower structures are very similar despite their size differences. However, the two families have distinct chemical properties as well as the obvious differences in life style of non-chlorophyll producing, parasitic vines, versus independent, photosynthesizing, green vines and herbs.
Etymology: Cuscuta is an ancient Latin name for dodder, probably of Arabic origin. Indecora means unattractive, though this species seems no less attractive than other species in the genus. Neuropetala means "with nerved petals", which refers to the nerves often present on the petal tube.