Dodder, Scaldweed

Cuscuta sp. 

kus-KEW-tuh

Cuscuta L. is a genus of parasitic plants in the plant family Convolvulaceae. The genus was named and described by Carl von Linnaeus in the first volume of the first edition of Species Plantarum in 1753.

As of 12-14-23 when this page was last updated, Plants of the World Online lists 219 species in the Cuscuta genus. It is a member of the plant family Convolvulaceae with 57 genera. Those numbers could change as updates are made on POWO.

The above map shows how widespread the Cuscuta genus is. Plants of the World Online lists 219 species in the genus worldwide. The USDA Plants Database has quite a list of species in North America which I didn’t count. Steyermark’s Flora of Missouri describes 10 species in Missouri alone. Of those 10 species, five are possible candidates for the species growing on the family farm in Pettis County in west-central Missouri.

THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH A BETTER POSITIVE ID.

I first noticed this strange creature growing on plants in the pond at the back of the farm on September 18, 2019. Until then, I never even heard of it. I was taking photos of wildflowers at the time so I thought I would take photos of this life form to see if I could make some kind of an ID.

Normally, flowers are pretty much a necessary thing when making a positive ID but something was weird. There didn’t appear to be any flowers or leaves. Just a lot of vines and these strange-looking balls. I took photos anyway, a lot of them, because you never know how many will turn out good and how many will be blurry. That’s the problem sometimes when the wind is blowing and when taking close-ups.

So, after I had taken photos of this weird plant and other wildflowers as well, I went back to the house and uploaded the photos on the computer. I sorted through them, wrote captions for the wildflowers I knew then set out to ID what I didn’t. One easy trick to get me started in the right direction for some plants is to drag and drop photos on iNaturalist. The website suggested this plant was either Cuscuta campestris or Cuscuta gronovii. Then I went to the Missouri Plants website and several others to do a bit of reading. What I found out was very interesting. Cuscuta species are parasitic plants that feed off other species… Of the five Cuscuta species that “could” be found on my farm, I could probably narrow that down a bit… Many websites say ID can be very difficult.

Once the tiny seeds germinate the seedlings grow toward potential host plants perhaps in response to volatiles released by the host. If a suitable host plant isn’t found within 5-10 days, the seedling will die. Once a host plant is found, they twine around the plant’s stems and attach to it by suckers called haustoria.  Once it is established on a host plant, its roots die and it becomes completely dependent on the host.

The flowers are very weird. I didn’t think there were any flowers present until I started looking at photos online. The above photo shows flowers but they may be almost finished. The balls are the fruit…

Since these plants were growing in the water at the edge of the pond, their host has to also be a water-loving species. Some species of Cuscuta are fairly host-specific, while others like a varied diet that allows them an extended range. They have very low levels of chlorophyll which is why they depend on a host plant for survival.

Where I live in Pettis County, several other counties are within a few miles. Henry County is across the street… Cuscuta species found in this area, according to Steyermark’s Flora of Missouri, include Cuscuta cuspidata (Cusp Dodder), Cuscuta glomerata (Rope Dodder), Cuscuta indecora (Largeseed Dodder, Large Alfalfa Dodder, Pretty Dodder) (only 7 counties), Cuscuta pentagona (Field Dodder) and Cuscuta polygononum (Smartweed Dodder). I can easily rule out several species…

I haven’t noticed any of these plants since 2019 but I will keep checking…

I have enjoyed photographing and learning about the many wildflowers growing on the farm and in other areas. I have grown over 500 different plants and identified over 250 species of wildflowers (most have pages listed on the right side of this site). I am not an expert, botanist, or horticulturalist. I just like growing, photographing and writing about my experience. I rely on several websites for ID and a horticulturalist I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.

I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at thebelmontrooster@yahoo.com. I would enjoy hearing from you.

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS)
INTERNATIONAL PLANT NAMES INDEX (GENUS)
TROPICOS (GENUS)
FLORA OF MISSOURI (GENUS)
WORLD FLORA ONLINE (GENUS)
WIKIPEDIA (GENUS)
MISSOURI PLANTS
MSU-MIDWEST WEEDS AND WILDFLOWERS
USDA PLANTS DATABASE
UNIVERSITY OF WISCONSIN

NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. Some websites have hundreds and even many thousands of species to keep up with. Accepted scientific names change periodically and it can be hard to keep with as well. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is one of the most reliable and up-to-date plant databases and they make updates regularly. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂