My sincere thanks to Dan Spaulding curator of the Anniston Museum of Natural History who directed my attention to a paper he wrote about Dodders. Hooray! It is challenging to find accurate, detailed information to identify Cuscuta so this key is most welcome. Check out the link! http://www.phytoneuron.net/2013Phytoneuron/74PhytoN-CuscutaAlabama.pdf

Each plant included in this project will be either a holoparasite, a hemiparasite, or a host. If a plant is some color other than green because it contains no chlorophyll, assume it is a holoparasite and is unable to produces its own food. Remember "holo" means "whole" or "entire." Dodder (Cuscuta) a twining vine colored yellow or orange is an example of a holoparasite.
However, a hemiparasite might well have chlorophyll of its own, but still take much of its nutrition from other plants. Remember "hemi" means "half" just like "semi." American Mistletoe (Phorodendron leucarpum) is green and it is a hemiparasite. Yet it is easy to tell that it is a parasitic plant because it is alway growing out of the branches or trunk of its tree host. Some other hemiparasites are much harder to recognize as parasites at all because they do not have as visible a relationship with their hosts as American Mistletoe does. Most hemiparasites are impossible to judge by appearance alone unlike holoparasites.
Whenever possible we will complete the relevant observation field to identify the plant host or the fact that a plant is being parasitized. After all, it would not do to mistake a parasitic plant for a host plant or vice versa.
Discover which plants are stealing nutrition from other plants not just in the forest, but even in your own backyard.