current LEO-entries:
Dictionary: Conium maculatum
• poison hemlock [bot.] = Gefleckter Schierling wiss.: Conium maculatum
• hemlock [bot.] = der Schierling wiss.: Conium maculatum

NOTE: This proposal suggests the following:
• poison hemlock [bot.] = Gefleckter Schierling wiss.: Conium maculatum NO CHANGE
• hemlock [bot.] = der Schierling Pl.: die Schierlinge wiss.: Conium maculatum

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http://www.oxforddictionaries.com/definition/...
hemlock
[…]
noun
1 A highly poisonous European plant of the parsley family, with a purple-spotted stem, fern-like leaves, small white flowers, and an unpleasant smell.
Conium maculatum, family Umbelliferae
[…]
Origin
Old English hymlice, hemlic, of unknown origin.

http://www.merriam-webster.com/dictionary/hemlock
hemlock
noun hem•lock \ˈhem-ˌläk\
[…]
1 a : any of several poisonous herbs (as a poison hemlock or a water hemlock) of the carrot family having finely cut leaves and small white flowers
[…]
Origin of HEMLOCK
Middle English hemlok, from Old English hemlic
First Known Use: before 12th century

http://dictionary.reference.com/browse/hemlock?s=t
hemlock
[hem-lok]
[…]
noun
1. a poisonous plant, Conium maculatum, of the parsley family, having purple-spotted stems, finely divided leaves, and umbels of small white flowers, used medicinally as a powerful sedative.
[…]

http://www.merriam-webster.com/dictionary/poi...
poison hemlock
noun
Definition of POISON HEMLOCK
: a large European biennial poisonous herb (Conium maculatum) of the carrot family that is naturalized in the United States and has finely divided leaves and small white flowers — compare water hemlock
First Known Use of POISON HEMLOCK
circa 1818

https://www.ahdictionary.com/word/search.html...
poison hemlock
n.
A highly poisonous plant (Conium maculatum) in the parsley family, native to Eurasia and Africa and widely naturalized in North America, having a stout stem, bipinnately compound leaves, and compound umbels of small white flowers.

https://en.wiktionary.org/wiki/poison_hemlock
poison hemlock
[…]
Noun
poison hemlock ‎(usually uncountable, plural poison hemlocks)
1. The European hemlock Conium maculatum, an extremely poisonous plant in the carrot family, Apiaceae
[…]

http://rbg-web2.rbge.org.uk/cgi-bin/nph-readb...
Conium maculatum
Authority (Brummitt & Powell): L.
Place of original publication: Sp. Pl. 243 (1753)
Native/Alien: N
English name: Hemlock

http://www.eol.org/pages/581784/overview
Conium maculatum
Hemlock

https://en.wikipedia.org/wiki/Conium_maculatum
Conium maculatum (hemlock or poison hemlock) is a highly poisonous perennial herbaceous flowering plant in the carrot family Apiaceae, native to Europe and North Africa.

http://plants.usda.gov/core/profile?symbol=COMA2
Conium maculatum L.
poison hemlock

http://www.omafra.gov.on.ca/english/crops/fac...
Name: Poison hemlock, Conium maculatum L.

**********

http://www.blumeninschwaben.de/Zweikeimblaett...
Gefleckter Schierling
(Conium maculatum)
[…]
English name:
Poison Hemlock

**********

http://www.floraweb.de/pflanzenarten/artenhom...
Wissenschaftlicher Name: Conium maculatum L.
Deutscher Name: Gefleckter Schierling
Familienzugehörigkeit: Apiaceae, Doldengewächse
Status: einheimisch

https://www.infoflora.ch/de/flora/1511-conium...
Conium maculatum L.
[…]
Gefleckter Schierling

http://www.dwds.de/?qu=Schierling
Schierling
mask., -s/-es, -e, fast nie im Plural
zu den Giftpflanzen gehörender, ein bis zwei Meter hoher weiß blühender Doldenblütler mit rübenförmigen Wurzeln

http://www.wissen.de/rechtschreibung/schierling
Schierling
Schier|ling 〈m. 1〉 (giftige Stoffe enthaltendes) weiß blühendes Doldengewächs [< mhd. scherlinc < mnddt. scharn, zu altnord. skarn „Mist“; entweder wegen des Geruchs oder wegen des Standorts]

http://www.duden.de/rechtschreibung/Schierling
Schierling, der
[…]
BEDEUTUNGSÜBERSICHT
(zu den Doldenblütlern gehörende) hochwachsende, sehr giftige Pflanze mit hohlem Stängel, fiederteiligen Blättern und großen weißen Doldenblüten

http://www.canoo.net/inflection/schierling:N:M
Flexion von Schierling
Wortklasse: Nomen
Genitiv Singular: Schierlings
Nominativ Plural: Schierlinge
Artikel: der
Flexionsklasse: s/e

Native & growing wild in Germany, Austria, Switzerland, UK, Ireland, all of Europe, northern & northeastern Africa, & western & central Asia. Naturalized in southern Africa, China, Australia, New Zealand, Pacific islands, Canada, US, Mexico, Central America, & South America.
Distribution / Verbreitung: in the Northern Hemisphere
in Europe
in Germany
in Switzerland
in the United States
Pictures / Bilder

Other English names (not proposed):
beaver poison
bunk
California fern
carrot fern
cashes
deadly hemlock
devil’s porridge
fool’s parsley
herb Bennet
musquash root
Nebraska fern
poison parsley
poison snakeweed
poison stinkweed
poisonroot
snakeweed
spotted corobane
spotted cowbane
spotted hemlock
spotted parsley
stinking hemlock
winter fern

Andere deutsche Namen (nicht vorgeschlagen):
das Bangenkraut
der Blutschierling
das Dollkraut
Echter Schierling
der Erdschierling
der Europa-Fleckenschierling
der Fleckenschierling
die Giftpetersilie
der Giftschierling
die Krottenpetersilie
der Mäuseschierling
das Schwindelkraut
der Sokrates-Schierling
Stinkender Schierling
der Tollkerbel
das Tollkraut
der Vogeltod
der Würgling
der Ziegendill

Taxonomic citation:
• Conium maculatum Linnaeus, Species Plantarum 1: 243. 1753.

Other scientific synonyms (not proposed):
• Coriandrum maculatum (L.) Roth (1788)
• Selinum conium (Vest) E.L. Krause (1904)
• Sium conium Vest (1806)

FYI
related LEO-entries:
aus dem Russisch-Wörterbuch:
Dictionary: [ru-de] Conium maculatum
• болиголо́в [бот.] м. = der Schierling Pl.: die Schierlinge wiss.: Conium maculatum

4168 - Apiaceae / Umbelliferae