This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Characters of the family. The filiform twining stems are parasitic on herbs and shrubs by numerous minute suckers. The seeds germinate in the soil and the plantlet attaches itself to its host, its root and lower portion soon perishing. The subsequent nutrition of the parasite is apparently wholly through its suckers. [Name from the Arabic]
About 100 species, of wide geographic distribution. Besides the following, some 15 others occur in the southern and western parts of North America. Known as Dodder, or Strangle-weed. Type species: Cuscnta europaea L.
* Corolla-scales crenulate; stigmas slender; capsule circumscissile; introduced species. Scales crenulate above, not incurved.
1. C. Epilinum.
Scales crenulate all around, strongly incurved.
2. C. Epithymum.
** Corolla-scales fringed; stigmas capitate; capsule indehiccent; native species. Sepals united below into a gamosepalous calyx.
Flowers very nearly sessile; corolla persistent at the base of the capsule. Corolla-scales ovate, fringed all around; calyx-lobes obtuse.
3. C. arvensis.
Corolla-scales abortive, or of a few processes; calyx-lobes acutish.
4. C. Polygonorum.
Flowers distinctly pedicelled; corolla enclosing or capping the capsule, or at length deciduous. Tips of the corolla-lobes incurved or reflexed.
Scales ovate, fringed all around; capsule enclosed by the corolla.
5. C. indecora.
Scales abortive, or of a few slender processes; corolla capping the capsule.
6. C. Coryli.
Corolla-lobes spreading or recurved.
Scales small, irregularly fringed; capsule depressed-globose.
7. C. Cephalanthi.
Scales long, fringed mainly above; capsule pointed. Corolla 1 1/2" long; capsule globose, short-pointed.
8. C. Gronovii.
Flowers 2" - 3" long; capsule oval, long-pointed.
9. C. rostrata.
Sepals separate, subtended by similar bracts.
Flowers cymose, pedicelled; scales short; bracts entire.
10. C. cuspidata.
Flowers closely sessile in dense clusters; bracts serrulate. Bracts few, broad, appressed; styles as long as the ovary.
11. C. compacta.
Bracts numerous, narrow, their tips recurved; styles longer than the ovary.
12. C. paradoxa.
Cuscuta Epilinum Weihe, Archiv. Apoth. 8: 54. 1824. Cuscuta densiflora Soyer-Willem. Act. Soc. Linn. Paris 4: 281. 1826.
Stems very slender, yellow or red; flowers sessile in dense clusters, yellowish white, about 1 1/2" long. Calyx hemispheric, 5-lobed, the lobes acute, nearly as long as the corolla-tube; corolla yellowish-white, short, cylindric, becoming urceolate, 5-lobed, the lobes ovate, acutish, spreading, its scales short, erect, less than one-half the length of the tube, 2-cleft or emarginate, crenulate above, the crenulations not extending to the base; stigmas linear-filiform; capsule circumscissile, the withering-persistent corolla borne on its summit.
On flax. Nova Scotia to New Jersey and Pennsylvania. Introduced from Europe. Native also of Asia. July-Aug.