Perfoliate Tinker’s Weed, Fever Root, Wild Coffee, Feverwort, Common Horse Gentian, Late Horse Genetian

Triosteum perfoliatum

try-OH-SEE-um  per-foh-lee-AY-tum

Synonyms of Triosteum perfoliatum (4) (Updated on 12-11-23 from Plants of the World Online): Karpaton hastatum Raf., Triosteum connatum Raf., Triosteum majus Michx., Triosteum obovatum Raf.

Triosteum perfoliatum L. is the accepted scientific name for this species. The genus and species were both named and described as such by Carl von Linnaeus in the first volume of the first edition of Species Plantarum in 1753.

As of 12-11-23 when this page was last updated, Plants of the World Online lists 6 species in the Triosteum genus. It is a member of the plant family Caprifoliaceae with a total of 33 genera. Those numbers could change periodically as updates are made on POWO.

The above distribution map for Triosteum perfoliatum is from Plants of the World Online. Areas in green are where the species is native. The map on the USDA Plants Database is the same.

The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist are continually updated as members post new observations. 

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

I found this neat species growing in the woods on a friend’s farm while wildflower hunting on May 10 (2020). I didn’t know what it was so I took LOTS of photos so I could make a positive ID. Later on, I uploaded the photos on iNaturalist and found out it was Triosteum perfoliatum. Common names include Perfoliate Tinker’s Weed, Fever Root, Wild Coffee, Feverwort, and possibly others.

The Triosteum perfoliatum is a perennial wildflower that grows up to 3 1/2 feet tall. Its strong stems have short average length soft hair. Some information says the stems are unbranched while others say they could branch out at the base.

The species produces 1-5 flowers, which are sessile (without peduncles-flower stems) from the leaf axils (where the leaves join the stems).

Each flower produces a narrow tube-shaped corolla that is subtended by calyx lobes (sepals) with tiny hairs that are often tipped with glands. The corollas, about 1/2” long, have 5 lobes at their tip, and are dull to purplish-red, and sometimes with cream-colored spots near the base and inside. Sometimes the corolla is yellow or greenish-yellow. The corolla tube is swollen on one side (gibbous) at the base for collecting nectar. The corolla contains 5 stamens (male part of the flower) as long as the tube with yellow filaments and yellow anthers. The capitate 4-lobed stigma (female part) is above the 3-celled ovary (inferior).

The Triosteum perfoliatum produces flowers from May through July.

This species has amazing leaves. They grow in pairs opposite each other which grow at a 90° angle from the pair above and below. The longest leaves grow up to at least 8” long x 4” wide. The shape of the leaves is kind of weird and hard to explain… They are kind of broadly lance-shaped with a fairly pointed tip, they narrow somewhat then get wider toward the stem. The species name perfoliatum comes from the way some or all of its broadly winged leaves join together at the base and surround the stem. I think plants like that are really neat! The upper surface of the leaves can be hairless (glabrous) to slightly hairy while the undersurface I kind of whitish and covered with fine hair (pubescent).

Now, that is just neat any way you look at it… It looks like a single leaf with a stem running through the middle.

The leaves have a very prominent midrib (or midvein).

The undersides of the leaves have a kind of a whitish cast because of the short, soft hair.

The oddly shaped leaves grow in an opposite manner, meaning one across from another. With this species, the pairs above and below grow at a 90° angle from each other.

Several species of bees feed on the nectar produced by their flowers and a few species of caterpillars feed on the leaves.

The fruits (drupes) of this plant have been used as a coffee substitute.

At some point, I hope to find this species again to take more photos. The underbrush in this area can be terrible.

Triosteum perfoliatum was a very neat find that will keep me going back to its area of the woods.

I have enjoyed photographing and learning about the many wildflowers growing on the farm and in other areas. The farm I live on is in Windsor, Missouri in Pettis County (Henry County is across the street, and Benton and Johnson aren’t far away). I have grown over 500 different plants and identified over 250 species of wildflowers (most have pages listed on the right side of the blog). 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. Some sites may not be up-to-date but they are always a work in progress. 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 especially if you notice something is a bit whacky

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
TROPICOS (GENUS/SPECIES)
FLORA OF MISSOURI (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
USDA PLANTS DATABASE
MISSOURI PLANTS
MISSOURI DEPARTMENT OF CONSERVATION
iNATURALIST
WILDFLOWER SEARCH
DAVE’S GARDEN
ILLINOIS WILDFLOWERS
MINNESOTA WILDFLOWERS
KANSAS WILDFLOWERS AND GRASSES
PFAF (PLANTS FOR A FUTURE)
GO BOTANY
FRIENDS OF THE WILDFLOWER GARDEN

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. 🙂

PHOTOS FROM 2024…