Flower of the Day: Dodder

Cuscuta gronovii; Convolvulaceae (morning glory family)


See that tangled mess of yellow and orange threads?  That’s dodder.  It is actually a flowering plant, but it’s an obligate parasite, meaning it depends on a host plant for survival.  Almost entirely lacking chlorophyll, the rootless and leafless stem emerges from the ground and finds a host plant to attach to, then wraps itself around the plant as it grows, penetrating the host in order to draw nutrition from it.  Later in the season it flowers and sets seed, then dies.

Dodder is native to most of the United States, but that doesn’t mean it isn’t a pest.  It’s a major problem for certain agricultural crops (cranberry and blueberry, among others), is a federally listed noxious weed, and is listed by thirteen states as noxious and/or prohibited and/or restricted and/or quarantined… you get the idea.  Look at these stems reaching out from the host plant!  (click on the image)


As a perpetually curious wildflower enthusiast I was a little excited to find it. On the other hand, I’m a little worried.  The greater Carderock-Marsden Tract area has enough problems from alien invasives without having to deal with dodder, too.

The name “dodder” comes from the Middle High German word for egg yolk.

Good info about dodder from the University of Massachusetts.

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