Common St. John’s Wort, Perforate St. John’s Wort, Klamath Weed
Synonyms of Hypericum perforatum (5)(Updated on 12-27-22 from Plants of the World Online): Hypericum perforatum f. floribundum Sennen (1924)(nom. nud.), Hypericum perforatum var. vulgare Spenn. (1829)(nom. illeg.), Hypericum officinale Gaterau (1789)(nom. illeg.), Hypericum officinarum Crantz (1763)(nom. illeg.), Hypericum vulgare Lam. (1779)(nom. illeg.)
Synonyms of Hypericum perforatum subsp. perforatum (21)(Updated on 12-27-22 from POWO): Hypericum assurgens Peterm. ex Rouy (1896), Hypericum deidesheimense Sch.Bip. ex Trevir. (1861), Hypericum lineolatum Jord. (1855), Hypericum marylandicum Biroli ex Colla (1833), Hypericum perforatum var. albiflorum Choisy (1824), Hypericum perforatum var. alpinum Parl. (1875), Hypericum perforatum var. anomalum Frid. (1887), Hypericum perforatum f. brevispathum A.Fröhl. (1911), Hypericum perforatum var. decompositum Nyár. (1939), Hypericum perforatum var. latifolium W.D.J.Koch (1844), Hypericum perforatum subsp. lineolatum (Jord.) Berher (1887), Hypericum perforatum subvar. lineolatum (Jord.) Rouy (1896), Hypericum perforatum f. lineolatum (Jord.) A.Fröhl. (1911), Hypericum perforatum var. lineolatum (Jord.) Hayek (1925), Hypericum perforatum f. lucidum A.Fröhl. (1911), Hypericum perforatum var. pellucidum O.Schwarz (1965)(no type indicated.), Hypericum perforatum var. petiolatum Peterm. (1846), Hypericum perforatum var. semihumifusum Nyár. (1955), Hypericum perforatum subsp. vulgare (Schimp. & Spenn.) A.Fröhl. (1911)(not validly publ.), Hypericum pseudoperforatum Bertol. (1844), Hypericum vulgare Bubani (1901)(nom. illeg.)
Hypericum perforatum L. is the accepted scientific name for this species of Hypericum. It was named and described as such by Carl von Linnaeus in the second volume of the first edition of Species Plantarum in 1753.
Accepted Infraspecific Names (4)(Updated on 12-26-22 from POWO): Hypericum perforatum subsp. chinense N.Robson (2002), *Hypericum perforatum subsp. perforatum (autonym), Hypericum perforatum subsp. songaricum (Ledeb. ex Rchb.) N.Robson (2002), Hypericum perforatum subsp. veronense (Schrank) H.Lindb. (1906). *When an infraspecific taxon is named, an autonym (“type-specimen”) is automatically generated whose description is closest to the (original) species. All have their own list of synonyms… The autonym is the only one found in North America.
The genus Hypericum Tourn. ex L. was named and described as such by Carl von Linnaeus in the second volume of the first edition of Species Plantarum in 1753. He gave credit to Joseph Pitton de Tournefort for first naming and describing the genus.
As of 12-26-22 when this page was last updated, Plants of the World Online lists 510 species in the Hypericum genus. It s a member of the plant family Hypericaceae with 6 genera. Those numbers could change as updates are made on POWO.
The above distribution map for Hypericum perforatum is from Plants of the World Online. Areas in green are where the species is native and purple is where it has been introduced. The map on the USDA Plants Database for the United States and Canada is similar.
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 POSITIVE ID.
I was at a friend’s home south of town on July 11 in 2020 and it was time for him to take his daily walk. He had surgery and part of his recovery was to take a walk every day. So, I went with him down the road then we turned down another road. Luckily, I had my camera with me when I spotted a familiar-looking plant. It didn’t have flowers but the leaves reminded me of the Hypericum punctatum (Spotted St. John’s Wort) that I identified on my farm in 2019.
It was in a shady area so many of the photos I took weren’t that great…
I tried to zoom in to get better close-ups of the translucent spots on the leaves, but it didn’t work so well. Still, the photos I took were enough to get a positive ID. I believed it was a Hypericum perforatum commonly known as the Common St. John’s Wort. I intended to go back later to get photos of its flowers, but I became busy doing this and that and I didn’t go back.
When I was writing this page, I thought I would try zooming on photo #722-3 to show the translucent spots on the leaves. You can hold a leaf up to the sun and the light will shine through.
Then, on June 22 in 2022, I was traveling on a back road toward his home again and spotted several colonies of plants with yellow flowers. When I came back, I noticed a colony on a corner at the south end of County Line Road. Of course, I got out of the car to give them a closer look and take a few photos. I had found a colony of what I thought was a St. John’s Wort… The sun was very bright, but I took a lot of photos anyway. You know, sometimes taking plant photos in bright sun doesn’t work out that great. I uploaded the good ones on iNaturalist and the first suggested ID was Hypericum perforatum. I went to the Missouri Plants website to double-check check and this colony of plants was indeed Hypericum perforatum…
Making updates to this site is a winter project. I have several new pages to publish and lots of photos to add as well. Once updates are finished, I will go back and add more information and write descriptions on the new plant pages. It takes a while for me to write descriptions but I want to write new pages and get the photos online anyway. There are several very good websites that have GREAT descriptions at the bottom of the page.
I will write descriptions as soon as I have time.
I live on the family farm 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 page). 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 few horticulturalists I contact if I cannot figure them out. Wildflowers can be variable from location to location, so that can be 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 firstname.lastname@example.org. 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)
FLORA OF MISSOURI (GENUS/SPECIES)
FLORA OF NORTH AMERICA (GENUS/SPECIES/SUBSP.)
WORLD FLORA ONLINE (GENUS/SPECIES)
USDA PLANTS DATABASE
USDA PLANT GUIDE
MISSOURI BOTANICAL GARDEN
MISSOURI CONSERVATION DEPARTMENT
FRIENDS OF THE WILDFLOWER GARDEN
KANSAS WILDFLOWERS AND GRASSES
LADY BIRD JOHNSON WILDFLOWER CENTER
MARYLAND BIODIVERSITY PROJECT
MICHIGAN STATE UNIVERSITY
NORTH CAROLINA STATE UNIVERSITY
PFAF (PLANTS FOR A FUTURE)
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 the most reliable and up-to-date plant database and they make updates on a regular basis. 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. 🙂