Laburnum

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Cladus: Rosids
Cladus: Eurosids I
Ordo: Fabales

Familia: Fabaceae
Subfamilia: Faboideae
Tribus: Genisteae
Genus: Laburnum
Species: L. alpinum – L. anagyroides

Nothospecies: L. × watereri
Name

Laburnum Fabr. (1759)

Type species: L. anagyroides Medik.

Synonyms

Homotypic
Cytisus sect. Laburnum (Fabr.) DC., Prodr. (Candolle) 2: 153. 1825.

Distribution
Native distribution areas:

Continental: Europe
Albania, Austria, Czechoslovakia, France, Germany, Greece, Hungary, Italy, Romania, Switzerland, Yugoslavia
Introduced into:
Argentina South, Baltic States, Belarus, Belgium, Central European Russia, Corse, East Himalaya, Great Britain, India, Ireland, Jawa, Krym, New Zealand North, New Zealand South, North Caucasus, Pakistan, South European Russia, Tasmania, Transcaucasus, Ukraine, West Himalaya

References: Brummitt, R.K. 2001. TDWG – World Geographical Scheme for Recording Plant Distributions, 2nd Edition

References
Primary references

Fabricius, P.C. 1759. Enumeratio Methodica Plantarum horti medici Helmstadiensis : subjuncta stirpium rariorum vel nondum satis extricatarum descriptione. viii + 239 pp., Helmstadii [Helmstedt]: Litteris Ioannis Drimbornii. Universtitätsbibliothek Braunschweig Gallica Google Books Reference page. Enum.: 228,

Additional references

Farr, E.R. & Zijlstra, G. (eds.) 1996 onwards. Laburnum in Index Nominum Genericorum (Plantarum). Accessed: 2012 Jan 21.

Links

Govaerts, R. et al. 2021. Laburnum in Kew Science Plants of the World online. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the internet. Accessed: 2021 Jan 22. Reference page.
International Plant Names Index. 2021. Laburnum. Published online. Accessed: Jan 22 2021.
Tropicos.org 2021. Laburnum. Missouri Botanical Garden. Published on the internet. Accessed: 2021 Jan 22.
Hassler, M. 2021. Laburnum. World Plants: Synonymic Checklists of the Vascular Plants of the World In: Roskovh, Y., Abucay, L., Orrell, T., Nicolson, D., Bailly, N., Kirk, P., Bourgoin, T., DeWalt, R.E., Decock, W., De Wever, A., Nieukerken, E. van, Zarucchi, J. & Penev, L., eds. 2021. Species 2000 & ITIS Catalogue of Life. Published on the internet. Accessed: 2021 Jan 22. Reference page.

Vernacular names
العربية: قصاص
azərbaycanca: Qızılıakasiya
català: Laburn
čeština: Štědřenec
dansk: Guldregn
Deutsch: Goldregen
dolnoserbski: Žołta akacija
English: Laburnum
Esperanto: Orpluvo
español: Laburno
فارسی: درخت پروانه
suomi: Kultasateet
français: Cytise
Gaeilge: Beallaí
hrvatski: Negnjil
hornjoserbsce: Kitkowc
magyar: Aranyeső
íslenska: Gullregn
lietuvių: Pupmedis
македонски: Доброцвет
norsk: Gullregnslekta
polski: Złotokap
русский: Бобовник
संस्कृतम्: मरुद्रुमः
slovenčina: štedrec
svenska: Gullregnssläktet
Türkçe: Altınyağmuru
українська: Золотий дощ
中文: 毒豆属

Laburnum, sometimes called golden chain or golden rain, is a genus of two species of small trees in the subfamily Faboideae of the pea family Fabaceae. The species are Laburnum anagyroides—common laburnum and Laburnum alpinum—alpine laburnum. They are native to the mountains of southern Europe from France to the Balkans.

Some botanists include a third species, Laburnum caramanicum, but this native of southeast Europe and Anatolia is usually treated in a distinct genus Podocytisus, more closely allied to the Genisteae (brooms).

Description

The Laburnum trees are deciduous. The leaves are trifoliate, somewhat like a clover; the leaflets are typically 2–3 cm (0.8–1.2 in) long in L. anagyroides and 4–5 cm (1.5–2 in) long in L. alpinum.

They have yellow pea-flowers in pendulous leafless racemes 10–40 cm (4–15.5 in) long in spring, which makes them very popular garden trees. In L. anagyroides, the racemes are 10–20 cm (4–8 in) long, with densely packed flowers; in L. alpinum the racemes are 20–30 cm (8–12 in) long, but with the flowers sparsely along the raceme.[2] The fruit develops as a pod and is extremely poisonous.[3]

The yellow flowers are responsible for the old poetic name 'golden chain tree' (also written as golden chaintree or goldenchain tree).
Laburnum tree in full flower

All parts of the plant are poisonous, although mortality is very rare.[4] Symptoms of laburnum poisoning may include intense sleepiness, vomiting, convulsive movements, coma, slight frothing at the mouth and unequally dilated pupils. In some cases, diarrhea is very severe, and at times the convulsions are markedly tetanic. The main toxin in the plant is cytisine, a nicotinic receptor agonist.

It is used as a food plant by the larvae of some Lepidoptera species, including the Palearctic moth, the buff-tip.
Species
Accepted binomials

Laburnum comprises the following species:[5][6][7]

Laburnum alpinum (Mill.) Bercht. & J. Presl
Laburnum anagyroides Medik.

Species names with uncertain taxonomic status

The status of the following species is unresolved:[7]

Laburnum album J.Presl
Laburnum arboreum J.Presl
Laburnum biflorum G.Nicholson
Laburnum fragrans Griseb.
Laburnum grandiflorum (DC.) J.Presl
Laburnum heuffelii Wierzb. ex Fuss
Laburnum ianigerum J. Presl
Laburnum intermedium Dippel
Laburnum jacquinianum Dalla Torre & Sarnth.
Laburnum jaquinianum Dieck
Laburnum laburnum (L.) Voss
Laburnum laburnum Dörfl.
Laburnum lanigerum J.Presl
Laburnum linneanum Dieck
Laburnum monadelphum Pritz.
Laburnum nigricans J.Presl
Laburnum nigricanum Fuss
Laburnum nubigenum J.Presl
Laburnum patens J.Presl
Laburnum pendulum Raf.
Laburnum praecox Fuss
Laburnum purpurascens hort. & Vilm.
Laburnum purpureum (Scop.) Drapiez
Laburnum ramentaceum (Sieber) K.Koch
Laburnum rochelii Wierzb. ex Fuss
Laburnum serotinum Hort. ex Dippel
Laburnum sessilifolium J.Presl
Laburnum spinosum J.Presl
Laburnum tardiflorum auct.
Laburnum triflorum J.Presl
Laburnum variabile hort. & Vilm.
Laburnum weldeni Griseb. ex Lavall.
Laburnum weldenii Griseb. ex Lavallée

Hybrids

The following hybrids have been described:[7]

Laburnum × watereri (Wettst.) Dippel (L. alpinum × L. anagyroides)

There is also a graft hybrid, + Laburnocytisus 'Adamii' Lavallée.
Uses
Woodworking

Laburnum has historically been used for cabinetmaking and inlay, as well as for musical instruments. In addition to such wind instruments as recorders and flutes, it was a popular wood for Great Highland Bagpipes[8] before taste turned to imported dense tropical hardwoods such as Brya ebenus (cocus wood), ebony, and Dalbergia melanoxylon (African monkeywood).[9] The heart-wood of a laburnum may be used as a substitute for ebony or rosewood. It is very hard and a dark chocolate brown, with a butter-yellow sapwood.
Freshly cross cut laburnum with visible heart-wood
Cultivation

Laburnum species and hybrids are cultivated as ornamental trees for gardens and parks. They are also trained as espaliers on pergolas, for ceilings of pendant flowers in season. In its natural form, Laburnum is a shrubby, multi-branched tree, but it is often pruned to maintain a single trunk which displays the smooth green bark.

Gardeners are advised to remove the spent seedpods after flowering because they sap the strength of the tree and are the most poisonous part.[10] Generally Laburnum does not perform well in hot climates, and has a reduced life-span if grown in climates with warm winters. Afternoon shade and the occasional deep watering are advisable in areas with hot, dry summers. They do best in climates with moderate winter and summer temperatures, ideally Oceanic climates like those of the Pacific Northwest and Northern Europe.[11] Laburnum trees are ubiquitous in England, Wales, Scotland and Ireland, where they are commonly planted as lawn specimens or in shrub borders.

Most garden specimens are of the hybrid between the two species, Laburnum ×watereri 'Vossii' (Voss's laburnum), which combines the longer racemes of L. alpinum with the denser flowers of L. anagyroides; it also has the benefit of low seed production. It has gained the Royal Horticultural Society's Award of Garden Merit.[12][13]
References

Cardoso D, Pennington RT, de Queiroz LP, Boatwright JS, Van Wyk BE, Wojciechowski MF, Lavin M (2013). "Reconstructing the deep-branching relationships of the papilionoid legumes" (PDF). S Afr J Bot. 89: 58–75. doi:10.1016/j.sajb.2013.05.001.
Parnell, J. and Curtis, T. 2012. Webb's An Irish Flora. Cork University Press. ISBN 978-185918-4783
Kilbracken, J. 1989. Easy way guide Trees. Larousse. ISBN 0-7523-0027-X
Forrester R.M. (1979). "Have you Eaten Laburnum?". The Lancet. 313 (8125): 1073. doi:10.1016/S0140-6736(79)92963-5. PMID 86787. S2CID 38961471.
"ILDIS LegumeWeb entry for Laburnum". International Legume Database & Information Service. Cardiff School of Computer Science & Informatics. Retrieved 11 April 2014.
USDA; ARS; National Genetic Resources Program. "GRIN species records of Laburnum". Germplasm Resources Information Network—(GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. Archived from the original on 24 September 2015. Retrieved 11 April 2014.
"The Plant List entry for Laburnum". The Plant List. Royal Botanic Gardens, Kew and the Missouri Botanical Garden. 2013. Retrieved 11 April 2014.
Rendle BJ (1969). World Timbers: Europe and Africa. 1. Univ of Toronto Press. p. 40. ISBN 978-0802015709.
Dickson J. (2009). The Highland bagpipe: music, history, tradition. Ashgate Publishing, Ltd. p. 50. ISBN 978-0-7546-6669-1.
Kathleen Norris Brenzel, ed. (2007). Sunset Western Garden Book. p. 429.
"Laburnum x watereri 'Vossii'". Missouribotanicalgarden.com. Retrieved 18 December 2017.
"Plant Selector—Laburnum ×watereri 'Vossii'". Royal Horticultural Society. Retrieved 20 May 2013.
"AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 57. Retrieved 17 March 2018.