Allium sphaerocephalon

Allium sphaerocephalon
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Order:	Asparagales
Family:	Amaryllidaceae
Subfamily:	Allioideae
Genus:	Allium
Subgenus:	A. subg. Allium
Species:	A. sphaerocephalon
Binomial name
	Allium sphaerocephalon; L.
Synonyms
	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. ;

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.^[2] 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).^[3]^[4] Its native range extends to northern Africa and to western Asia as far east as Iran.^[5] It is also reportedly naturalised in New York State in the United States.^[6] In England it grows wild only in the Avon Gorge so is known locally as the Bristol onion.^[7]

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.^[5]

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

This plant has gained the Royal Horticultural Society's Award of Garden Merit.^[8]

Description

Allium sphaerocephalon produces egg-shaped bulbs. Small bulblets are present under the outer layer of the stem (making the plant potentially invasive when grown in gardens). Flowers are borne on a scape up to 50 cm in height, in a spherical to egg-shaped umbel, 1–6 cm in diameter, tightly packed with many flowers crowded together. The relatively small size of the umbel relative to the height of the stem makes this one of those described as "drumstick alliums". Individual flowers are reddish-purple and are occasionally replaced by bulbils (again making this a potentially invasive species).^[3]

Subspecies and varieties

^[1]

Allium sphaerocephalon var. aegaeum (Heldr. & Halácsy) Hayek - Aegean Islands
Allium sphaerocephalon subsp. arvense (Guss.) Arcang. - Sicily, Malta, Albania, Greece, Turkey, Cyprus, Syria, Lebanon, Egypt, Algeria, Tunisia, Morocco^[9]
Allium sphaerocephalon subsp. laxiflorum (Guss.) Giardina & Raimondo - Sicily^[9]
Allium sphaerocephalon subsp. sphaerocephalon - much of Europe plus Morocco, Canary Islands, Middle East
Allium sphaerocephalon subsp. trachypus (Boiss. & Spruner) K.Richt. - Greece and Turkey incl Aegean Islands^[9]

Formerly included

^[1]

Allium sphaerocephalon subsp. durandoi, now called Allium ebusitanum
Allium sphaerocephalon subsp. ebusitanum, now called Allium ebusitanum
Allium sphaerocephalon subsp. rollii, now called Allium amethystinum
Allium sphaerocephalon subsp. sardoum, now called Allium guttatum subsp. sardoum
Allium sphaerocephalon var. scaberrimum, now called Allium scaberrimum

References

^ ^a ^b ^c Kew World Checklist of Selected Plant Families
^ E.g. Mathew, Brian (1978), The Larger Bulbs, London: B.T. Batsford (in association with the Royal Horticultural Society), ISBN 978-0-7134-1246-8
^ ^a ^b Davies, Dilys (1992), Alliums : the ornamental onions, London: B.T. Batsford (in association with the Hardy Plant Society), ISBN 978-0-7134-7030-7, p. 135
^ Altervista Flora Italiana, Schede di botanica, Allium sphaerocephalon
^ ^a ^b Missouri Botanical Garden, Gardening Help, Allium sphaerocephalon
^ Biota of North America Program, Allium sphaerocephalon
^ "Bristol Onion". Bristol University. Retrieved 2014-10-08.
^ "RHS Plantfinder - Allium sphaerocephalon". Royal Horticultural Society. 2016. Retrieved 5 January 2018.
^ ^a ^b ^c Kew Royal Botanical Garden, London, Allium sphaerocephalon

External links

"Allium sphaerocephalon". Plants for a Future.
Comprehensive profile for Allium sphaerocephalon from the website MaltaWildPlants.com

[gogreen-1] Kew World Checklist of Selected Plant Families

[2] E.g. Mathew, Brian (1978), The Larger Bulbs, London: B.T. Batsford (in association with the Royal Horticultural Society), ISBN 978-0-7134-1246-8

[Davies1992-3] Davies, Dilys (1992), Alliums : the ornamental onions, London: B.T. Batsford (in association with the Hardy Plant Society), ISBN 978-0-7134-7030-7, p. 135

[4] Altervista Flora Italiana, Schede di botanica, Allium sphaerocephalon

[ravenisgod-5] Missouri Botanical Garden, Gardening Help, Allium sphaerocephalon

[6] Biota of North America Program, Allium sphaerocephalon

[7] "Bristol Onion". Bristol University. Retrieved 2014-10-08.

[8] "RHS Plantfinder - Allium sphaerocephalon". Royal Horticultural Society. 2016. Retrieved 5 January 2018.

[q-9] Kew Royal Botanical Garden, London, Allium sphaerocephalon

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