Poison Hemlock
Conium maculatum
Appearance 2
It is an herb with a hollow purple-spotted stem that can reach eight feet in height. It omits a parsnip-like odor whenever it is crushed. Flowers start to grow on the plant in the second year, and they are in small, white, umbrella-shaped clusters.
Introduction 2
It was introduced in the 1800’s from Europe as an ornamental plant.
Similar Native Species 2
Wild parsnip (Pastinaca sativa) lacks purple mottling on its stems and petioles, although it is otherwise very similar in appearance to poison hemlock. Water hemlock (Cicuta maculata) shares many characteristics with poison hemlock including hairless stems that have purple mottling and compound leaves. Unlike poison hemlock, water hemlock usually has a cluster of fleshy taproots at its base. Also, habitat may help to distinguish the two as water hemlock grows in marshes and other very wet sites and is generally confined to the central plains and mountainous areas of North America. Giant hogweed (Heracleum mantegazzianum) is generally taller and has leaves as long as 3 feet and large white flower clusters, although its stems are also purple-spotted.
Impacts on Ecosystem 2
One plant can produce over 30,000 seeds that are small enough to be transported by the wind which means that they can rapidly establish in disturbed areas in particular. Seeds are extremely poisonous to humans and livestock which can cause major problems if it starts to grow where cattle graze.
Citations 2
http://www.dcnr.state.pa.us/cs/groups/public/documents/document/dcnr_010237.pdf
http://www.oardc.ohio-state.edu/weedguide/single_weed.php?id=114
Sources and Credits
- (c) Mick Talbot, some rights reserved (CC BY), http://www.flickr.com/photos/25258702@N04/3617902134
- (c) gburg2016, some rights reserved (CC BY-SA)
More Info
- iNat taxon page
- African Plants - a photo guide
- Atlas of Living Australia
- Biodiversity Heritage Library
- BOLD Systems BIN search
- Calflora
- CalPhotos
- Catalogo de Plantas y Líquenes de Colombia
- eFloras.org
- Flora Digital de Portugal
- Flora of North America (beta)
- Global Biodiversity Information Facility (GBIF)
- Go Botany
- HOSTS - a Database of the World's Lepidopteran Hostplants
- IPNI (with links to POWO, WFO, and BHL)
- Jepson eFlora
- Maryland Biodiversity Project
- NatureServe Explorer 2.0
- NBN Atlas
- New Zealand Plant Conservation Network
- OregonFlora.org
- SEINet Symbiota portals
- Tropicos
- USDA PLANTS database
- VASCAN by Canadensys
- World Flora Online
iNat Map
| Category | Invasive Species |
|---|
