Conium maculatum (Poison Hemlock)

Conium maculatum (Poison Hemlock) on 5-22-22, #882-2.

Poison Hemlock, Spotted Hemlock, Poison Parsley, California Fern, Nebraska Fern, Deadly Hemlock, Poison Fool’s Parsley, Winter Fern

Conium maculatum

koh-NI-um mak-yuh-LAH-tum

Synonyms of Conium maculatum (17) (Updated on 8-2-22 from Plants of the World Online): Cicuta major Lam., Cicuta officinalis Crantz, Conium ceretanum Sennen, Conium cicuta (Crantz) Neck., Conium croaticum Waldst. & Kit. ex Willd., Conium maculatum var. barceloi O.Bolòs & Vigo, Conium maculatum subsp. viride (DC.) Espeut, Conium maculosum Pall., Conium nodosum Fisch. ex Steud., Conium pyrenaicum Sennen & Elías, Conium sibiricum Steud., Conium strictum Tratt., Conium tenuifolium Mill., Coriandrum cicuta Crantz, Coriandrum maculatum (L.) Roth, Selinum conium E.H.L.Krause, Sium conium Vest

Conium maculatum L. is the accepted scientific name for the Poison Hemlock. The genus and species name was named and described as such by Carl von Linnaeus in the first volume of the first edition of Species Plantarum in 1753.

As of 8-3-22 when I wrote this page, Plants of the World Online by Kew lists 6 species in the Conium genus. It is a member of the plant family Apiaceae with 440 genera. Those numbers could change as updates are made on POWO.

Distribution map of Conium maculatum from Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://www.plantsoftheworldonline.org/. Retrieved on August 3, 2022.

The above distribution map for Conium maculatum is from Plants of the World Online. Areas in green are where the species is native and purple are 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.

Conium maculatum (Poison Hemlock) on 4-29-22, #875-11.

I have been seeing the Conium maculatum growing along the highways and backroads for several years but never stopped to take photographs. Mainly because I didn’t have my camera and I don’t have a cell phone. Then on April 29 (in 2022), I was mushroom hunting along the fence (actually across the fence) when I spotted a small plant that looked suspicious that had been mowed off and grown back. I had my camera so I took several photos and uploaded them on iNaturalist. Sure enough, it was a Conium maculatum… The plant that killed Socrates. I always wondered why such a deadly plant was allowed to spread to rampantly, and in very large colonies, along the highways.

Common names include Hemlock, Poison Hemlock, Spotted Hemlock, Poison Parsley, California Fern, Nebraska Fern, Poison Fool’s Parsley, Winter Fern, and possibly others.

Whatever you do, don’t handle this plant unless you know what you are doing. It may be neat looking, but remember it is deadly…

Conium maculatum (Poison Hemlock) on 4-29-22, #875-12.

I apologize for not writing descriptions when I wrote this page, but I was fairly busy. I will write descriptions as soon as I have time during the winter when I am not busy outside so I can catch up and make updates. There are several links at the bottom of the page that have great descriptions.

Conium maculatum (Poison Hemlock) on 4-29-22, #875-13.

 

Conium maculatum (Poison Hemlock) on 5-1-22, #877-5.

Then on May 1, I noticed a pretty good-sized Conium maculatum in an area behind the barn. I decided to let it grow so I could take photographs…

Conium maculatum (Poison Hemlock) on 5-1-22, #877-6.

Very streaked and spotted stems…

Conium maculatum (Poison Hemlock) on 5-1-22, #877-3.

 

I have enjoyed photographing and learning about the many wildflowers growing on the farm and in other areas nearby. My farm 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 200 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 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
DAVE’S GARDEN
MISSOURI PLANTS
MISSOURI BOTANICAL GARDEN
MSU-MIDWEST WEEDS AND WILDFLOWERS
iNATURALIST
WILDFLOWER SEARCH
ARKANSAS NATIVE PLANT SOCIETY
ILLINOIS WILDFLOWERS
MINNESOTA WILDFLOWERS
KANSAS WILDFLOWERS AND GRASSES
IOWA PLANTS
NORTH CAROLINA STATE UNIVERSITY
PFAF (PLANTS FOR A FUTURE)
GO BOTANY
MARYLAND BIODIVERSITY PROJECT
UNIVERSITY OF WASHINGTON/BURKE HERBARIUM
WILDFLOWERS OF NEW MEXICO
SEINet
SCIENCE DIRECT

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. 🙂