Editing Conium (section)

== Taxonomy ==
The genus name "Conium" references the Greek word ''koneios'' for 'spin' or 'whirl', alluding to the [[Vertigo|dizzying effects]] of the plant's poison after ingestion.<ref name=":5" /> In the vernacular, "hemlock" most commonly refers to the species ''C. maculatum'', but it also refers to ''[[Cicuta]]'' species (water hemlock), where both species are similar in physical features, and both are highly toxic.

The genus ''Conium'' was erected by [[Carl Linnaeus]] in 1753.<ref name=POWO_39839-1/> Several botanists, such as J.F.M. Cannon, G.H. Leute, and J.H. Ross, have historically made the argument that southern African species of ''Conium'' has few significant distinctions. Some even claim that the genus has no independent species at all. They argue that the populations in southern Africa "may be the result of the chance introduction of a few individuals which represented genetically a very limited range of the total variability of the species." Some believe that each species of ''Conium'' is synonymous to ''C. maculatum''. Others believe that there are two to three distinct southern African species of ''Conium''.<ref name=":6">{{Cite web|title=Conium chaerophylloides in Global Plants on JSTOR|url=https://plants.jstor.org/compilation/conium.chaerophylloides|access-date=2020-12-03|website=plants.jstor.org}}</ref>

=== History ===

Conium was known to ancient Greeks, who used it for its narcotic properties and in capital punishment. It was used for the execution, among others, of [[Socrates]] and [[Theramenes]].<ref>{{Cite book |last1=Burrows |first1=George E. |url=https://books.google.com/books?id=cqwvrIfINWgC&pg=PA67 |title=Toxic Plants of North America |last2=Tyrl |first2=Ronald J. |date=2013-01-29 |publisher=John Wiley & Sons |isbn=978-0-8138-2034-7 |language=en}}</ref>

''Conium maculatum'', also known as poison hemlock, was first described by Carl Linnaeus in his 1753 publication, [[Species Plantarum]]. It was the first described species within the genus. "Maculatum" means spotted, referencing the purple blotches characteristic of this species.<ref name=":3" />

''Conium chaerophylloides'' was described by Danish plant collector [[Christian Friedrich Ecklon]] (1795–1868) and German botanist [[Karl Ludwig Philipp Zeyher]]. In 1828, they came together in South Africa, forming a partnership. For the next decade, they built their collection, describing almost 2000 genera and species.<ref>{{Cite web|last=Östensson|first=Pia|title=Christian Friedrich Ecklon and Karl Ludwig Philipp Zeyher|url=https://www.nrm.se/en/forskningochsamlingar/botanik/botaniskhistoria/error.13420.html|access-date=2020-12-03|website=www.nrm.se|language=en}}</ref>

Both ''C. fontanum'' and ''C. sphaerocarpum'' were described by South African botanist [[Olive Mary Hilliard]] and English botanist [[Brian Burtt|Brian Laurence Burtt]]. Together, they published their classifications in the [[South African Journal of Botany]] in 1985.<ref>{{Cite web|title=Tropicos {{!}} Name - Conium fontanum Hilliard & B.L. Burtt|url=http://legacy.tropicos.org/name/100315049|access-date=2020-12-03|website=legacy.tropicos.org}}</ref>

=== Species ===
{{As of|2020|December}}, [[Plants of the World Online]] accepts six species:<ref name="POWO_39839-1">{{cite web |title=''Conium'' L. |work=Plants of the World Online |publisher=Royal Botanic Gardens, Kew|url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:39839-1 |access-date=2020-12-16 }}</ref>
*''[[Conium chaerophylloides]]'' <small>(Thunb.) Eckl. & Zeyh.</small>
*''[[Conium divaricatum]]'' <small>Boiss. & Orph.</small>
*''[[Conium fontanum]]'' <small>Hilliard & B.L.Burtt</small>
*''[[Conium hilliburttorum]]'' <small>Magee & V.R.Clark</small>
*''[[Conium maculatum]]'' <small>L.</small>
*''[[Conium sphaerocarpum]]'' <small>Hilliard & B.L.Burtt</small>

==== ''Conium chaerophylloides'' ====
''Conium chaerophylloides'', growing two to three meters tall, can be distinguished by its unique yellow-green flowers. Groups of many of these small flowers make up [[obconic]]al [[umbel]]s. The outer rays (individual flowers) form an angle with the point of attachment, giving the umbel a cone-like shape, which fans out from the base of the inflorescence. They produce round, 4&nbsp;mm long, dark brown or green fruit, with deep, lightly colored ridges.<ref name=":5" />

==== ''Conium fontanum'' ====
''Conium fontanum'' expresses a similar obconical umbel arrangement, but produces slightly larger fruit, and develops the white flowers characteristic of the other species in the ''Conium'' genus. The fruit is usually larger than 4&nbsp;mm long, with ridges of the same dark green or brown color as the rest of the ovary.<ref name=":5" /> These plants grow one to three meters tall, depending on the variety.<ref name=":7" />

==== ''Conium hilliburttorum'' ====
''Conium hilliburttorum'' has not always been recognized as a distinct species within the genus. Like ''C. sphaerocarpum'', these plants have white flowers grouped in hemispherical umbels and small fruit. However, these researchers argue that the fruit and ovary anatomy significantly distinguish them from ''C. sphaerocarpum''. They develop similar sized fruit; however, ''C. hilliburttorum'' fruit displays prominent ribs, whereas ''C. sphaerocarpum'' fruit is relatively smooth. ''C. hilliburttorum'' ovaries are covered in tubercules, or small lumpy outgrowths, like ''C. chaerophylloides'' fruit. However, ''C. chaerophylloides'' plants have yellow or green flowers, and they grow much larger fruit and are much taller.<ref name=":5" />

==== ''Conium maculatum'' ====
''Conium maculatum'' is distinguished by red or purple blotching along the hairless green stem. Some varieties of the southern African species express a moderate degree of blotching at the base of the stem, but most are simply green. It grows white flowers in umbrella-shaped clusters.<ref name=":3" />[[File:Conium maculatum - Köhler–s Medizinal-Pflanzen-191.jpg|center|thumb|295x295px|19th-century illustration of ''Conium maculatum''<br />(from ''[[Köhler's Medicinal Plants]]'')]]

==== ''Conium sphaerocarpum'' ====
''Conium sphaerocarpum'' produces similarly colored, but slightly smaller fruit, less than 3.5&nbsp;mm long. The ovary is relatively smooth, with almost completely flat, inconspicuous ridges. Additionally, the small white flowers are arranged in [[Sphere|hemispherical]] umbels. Each umbel's outer rays protrude horizontally, forming a semi-sphere shape, with the flat edge at the base of the umbel, and the dome pointing away from the point of attachment. This species tends to grow shorter than others within the genus.<ref name=":5" />