Taken from: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7496.html
Dodder has slender, twining or threadlike stems that vary from pale green to yellow or bright orange; the bright stems can be readily seen against the foliage of the host plants.
Native dodder can be leafless or have small, scalelike, triangular leaves about 1/16 inch long. The bell-shaped flowers are cream colored and about 1/8 inch long; they usually occur in clusters but occasionally are borne singly. Each flower produces a seed capsule with 2 to 3 seeds. Seeds have rough coats and vary in size depending on species but generally are about 1/16 inch in diameter. Seedlings are yellowish, threadlike, rootless, leafless stems.
Pest photo source
Dr. Dallas Peterson, Agronomy, KSU