Allium sphaerocephalon

{{Short description|Species of flowering plant}}

{{Speciesbox

| image= Alcalá de Henares (RPS 01-06-2024) Allium sphaerocephalon.png

| image_caption =

| taxon = Allium sphaerocephalon

| parent = Allium subg. Allium

| authority = L.

| synonyms =

{{collapsible list|bullets = true

|title=Species synonymy

|Allium aegaeum Heldr. & Halácsy

|Allium aestivum Tineo

|Allium approximatum Gren. & Gord.

|Allium arvense subsp. aestivum (Tineo) Nyman

|Allium arvense var. tenuiflorum Nyman

|Allium atroviolaceum Hornem. ex Steud.

|Allium borbasii A.Kern.

|Allium bosniacum Kumm. & Sendtn.

|Allium cornutum Kit.

|Allium crinitum Tausch

|Allium densiflorum De Not.

|Allium descendens L.

|Allium deseglisei Boreau

|Allium eminens Gren. ex Parl.

|Allium gherardii De Not.

|Allium lineare Ten.

|Allium loscosii K.Richt.

|Allium macrocephalum Kit.

|Allium margaritaceum var. robustum Maire

|Allium parviflorum L.

|Allium parviflorum Desv.

|Allium parvifolium Crantz

|Allium purpureum Loscos

|Allium pygmaeum E.Perrier

|Allium regnieri Maire

|Allium rotundum var. bosniacum (Kumm. & Sendtn.) Nyman

|Allium sardoum var. gherardii (De Not.) Nyman

|Allium schmidtianum Tausch

|Allium sphaerocephalon var. aegaeum (Heldr. & Halácsy) Hayek

|Allium sphaerocephalon var. approximatum (Gren. & Gord.) Nyman

|Allium sphaerocephalon var. bosniacum (Kumm. & Sendtn.) Asch. & Graebn.

|Allium sphaerocephalon var. crinitum (Tausch) Nyman

|Allium sphaerocephalon var. descendens (L.) Regel

|Allium sphaerocephalon subsp. descendens (L.) K.Richt.

|Allium sphaerocephalon f. prostratum Corill., Figureau & Godeau

|Allium sphaerocephalon var. purpureum Nyman

|Allium tenuiflorum Delastre

|Allium veronense Spreng.

|Kromon parviflorum (L.) Raf.

|Porrum crinitum (Tausch) Rchb.

|Porrum descendens (L.) Rchb.

|Porrum sphaerocephaluon (L.) Rchb.

}}

| synonyms_ref = [http://apps.kew.org/wcsp/namedetail.do?name_id=296631 Kew World Checklist of Selected Plant Families]

}}

Allium sphaerocephalon is a plant species in the Amaryllis family known as round-headed leek, round-headed garlic, ball-head onion, and other variations on these names. Drumstick allium is another common name applied to this species. Some publications use the alternate spelling Allium sphaerocephalum.E.g. {{Citation |last=Mathew |first=Brian |year=1978 |title=The Larger Bulbs |publication-place=London |publisher=B.T. Batsford (in association with the Royal Horticultural Society) |isbn=978-0-7134-1246-8 }} It is a bulbous herbaceous perennial plant.

Allium sphaerocephalon is found in the wild across all parts of Europe except in the northern and western countries (Scotland, Ireland, Netherlands, Scandinavia, and the Baltic States).[http://luirig.altervista.org/flora/taxa/index1.php?scientific-name=allium+sphaerocephalon Altervista Flora Italiana, Schede di botanica, Allium sphaerocephalon] Its native range extends to northern Africa and to western Asia as far east as Iran.[http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=e132 Missouri Botanical Garden, Gardening Help, Allium sphaerocephalon] It is also reportedly naturalised in New York State in the United States.[http://bonap.net/MapGallery/County/Allium%20sphaerocephalon.png Biota of North America Program, Allium sphaerocephalon] In England it grows wild only in the Avon Gorge so is known locally as the Bristol onion.{{cite web |url=http://www.bristol.ac.uk/centenary/look/cabinet/bristol-onion.html |title=Bristol Onion |publisher=Bristol University |access-date=2014-10-08}}

The species is prized by gardeners because of its striking floral display. The spherical "head" (technically an umbel) is borne on a long scape, up to 50 cm in height, usually in July. It can contain hundreds of deep purple flowers.

The specific epithet sphaerocephalon derives from ancient Greek, meaning "spherical head".

This plant has gained the Royal Horticultural Society's Award of Garden Merit.{{cite web | url= https://www.rhs.org.uk/Plants/870/i-Allium-sphaerocephalon-i/Details

| title = RHS Plantfinder - Allium sphaerocephalon

| publisher=Royal Horticultural Society | date=2016 | access-date=5 January 2018}}