Almost there: Help beaked dodder qualify for CV inclusion!

Every now and then I come across a species that should be fairly easy to identify, but there aren't enough confirmed sightings yet on iNaturalist for it to be included in the computer vision (CV) training set. One such species is beaked dodder (Cuscuta rostrata, currently 73 observations total).

Yes, I can see those of you familiar with dodder raise an eyebrow at the assertion that this is easy to ID (most dodders are anything but and community ID stays at genus level). However, this one is! If you come across this plant while hiking in the woods and know what to focus on, you can get a picture that allows for positive ID, and if you see this feature on photos on iNaturalist within the correct range you can quite confidently identify it.

The feature in question is a beak-like extension of the ovary that gives the plant one of its common names beaked dodder. Other dodders growing within its range (e.g. the otherwise very similar C. gronovii) do not have this type of beak on their round ovaries. Another feature that works in the field is to smell the flowers - this dodder species is said to have a very fragrant smell. The combination of correct range + fragrance + beak makes for a slam-dunk botanical ID that is sure to impress all your naturalist buddies!

Where to look for it:
This species is a Southern Appalachian endemic and occurs mostly in high elevation hardwood forests from West Virginia south to northeast Georgia. It likes shady areas (I've found it growing in seepage areas in deep shade) but may also be found in more open places like grassy balds. (The similar C. gronovii is essentially a wetland species, often found along stream margins and in marshes and wet fields.)

Host plants:
It does seem to have a wide range of host plants that it can latch onto. Numerous herbaceous species (I've seen it on Rudbeckia, Monarda, and Impatiens, for example) and a few woody species (Rubus, Hydrangea) appear to be preferred hosts. It can be grown on Coleus in cultivation, if anyone is so inclined.

Posted on October 09, 2022 06:24 PM by annkatrinrose annkatrinrose


I'll keep an eye out. I'm afraid that I tend to lump dodders into my "don't bother" category, but having a distinctive feature to watch for will make them more approachable.

Posted by eraskin about 1 year ago

We did it! As of the latest CV update, it is now included. Woohoo!

Posted by annkatrinrose 6 days ago


Posted by eraskin 4 days ago

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