''Laburnum'', sometimes called golden chain or golden rain, is a genus of two species of small

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

s in the subfamily

Faboideae The Faboideae are a subfamily of the flowering plant family Fabaceae or Leguminosae. An acceptable alternative name for the subfamily is Papilionoideae, or Papilionaceae when this group of plants is treated as a family. This subfamily is wide ...

of the pea family

Fabaceae The Fabaceae or Leguminosae,International Code of Nomenc ...

. The species are ''

Laburnum anagyroides ''Laburnum anagyroides'' ( syn. ''Cytisus laburnum''), the common laburnum, golden chain or golden rain, is a species of flowering plant in the subfamily Faboideae, and genus ''Laburnum''. '' Laburnum alpinum'' is closely related. It is native t ...

''—common laburnum and ''

Laburnum alpinum ''Laburnum alpinum'', the Scotch laburnum, Scottish laburnum or alpine laburnum, is a leguminous, (''Leguminosae''), deciduous tree. Description ''Laburnum alpinum'' is similar to '' Laburnum anagyroides'', it grows to by , at a fast rate. It i ...

''—alpine laburnum. They are native to the mountains of southern

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

from

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

to the

Balkans The Balkans ( ), also known as the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throughout the who ...

. Some botanists include a third species, ''Laburnum caramanicum'', but this native of southeast Europe and

Anatolia Anatolia, tr, Anadolu Yarımadası), and the Anatolian plateau, also known as Asia Minor, is a large peninsula in Western Asia and the westernmost protrusion of the Asian continent. It constitutes the major part of modern-day Turkey. The re ...

is usually treated in a distinct genus ''

Podocytisus ''Podocytisus caramanicus'' is a species of flowering plants in the family Fabaceae. It belongs to the subfamily Faboideae The Faboideae are a subfamily of the flowering plant family Fabaceae or Leguminosae. An acceptable alternative name f ...

'', more closely allied to the ''

Genisteae Genisteae is a tribe of trees, shrubs and herbaceous plants in the subfamily Faboideae of the family Fabaceae. It includes a number of well-known plants including broom, lupine (lupin), gorse and laburnum. The tribe's greatest diversity is in ...

'' (brooms).

Description

The ''Laburnum'' trees are

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

. The leaves are trifoliate, somewhat like a

clover Clover or trefoil are common names for plants of the genus ''Trifolium'' (from Latin ''tres'' 'three' + ''folium'' 'leaf'), consisting of about 300 species of flowering plants in the legume or pea family Fabaceae originating in Europe. The genus ...

; the leaflets are typically long in ''L. anagyroides'' and long in ''L. alpinum''. They have yellow pea-

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s in pendulous leafless

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

s long in spring, which makes them very popular garden trees. In ''L. anagyroides'', the racemes are long, with densely packed flowers; in ''L. alpinum'' the racemes are long, but with the flowers sparsely along the raceme. The fruit develops as a

pod Pod or POD may refer to: Biology * Pod (fruit), a type of fruit of a flowering plant * Husk or pod of a legume * Pod of whales or other marine mammals * "-pod", a suffix meaning "foot" used in taxonomy Electronics and computing * Proper ort ...

and is extremely poisonous. The yellow flowers are responsible for the old poetic name 'golden chain tree' (also written as golden chaintree or goldenchain tree). All parts of the plant are

poison Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...

ous, although mortality is very rare. 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 Cytisine, also known as baptitoxine, cytisinicline, or sophorine, is an alkaloid that occurs naturally in several plant genera, such as ''Laburnum'' and ''Cytisus'' of the family Fabaceae. It has been used medically to help with smoking cessati ...

, a nicotinic receptor

agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ago ...

. It is used as a food plant by the

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e of some

Lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...

species, including the

Palearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Sibe ...

moth, the

buff-tip The buff-tip (''Phalera bucephala'') is a moth of the family Notodontidae. It is found throughout Europe and in Asia to eastern Siberia. The species was first described by Carl Linnaeus in his 1758 10th edition of ''Systema Naturae''. Descrip ...

Species

Accepted binomials

''Laburnum'' comprises the following species: * ''

'' (Mill.) Bercht. & J. Presl * ''

'' Medik.

Species names with uncertain taxonomic status

The status of the following species is unresolved: * ''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: * ''Laburnum'' × ''watereri'' (Wettst.) Dippel (''L. alpinum'' × ''L. anagyroides'') There is also a

graft-chimaera In horticulture, a graft-chimaera may arise in grafting at the point of contact between rootstock and scion and will have properties intermediate between those of its "parents". A graft-chimaera is not a true hybrid but a mixture of cells, each w ...

, + ''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 Bagpipe The Great Highland bagpipe ( gd, a' phìob mhòr "the great pipe") is a type of bagpipe native to Scotland, and the Scottish analogue to the Great Irish Warpipes. It has acquired widespread recognition through its usage in the British milit ...

s before taste turned to imported dense tropical hardwoods such as ''

Brya ebenus ''Brya ebenus'', also known as espino de sabana, granadillo, cocus wood, cocuswood, and coccuswood, is a species of flowering tree in the pea family, Fabaceae, that is native to the Caribbean islands of Cuba and Jamaica. Horticulturally it is kno ...

'' (cocus wood),

ebony Ebony is a dense black/brown hardwood, coming from several species in the genus ''Diospyros'', which also contains the persimmons. Unlike most woods, ebony is dense enough to sink in water. It is finely textured and has a mirror finish when pol ...

, and ''

Dalbergia melanoxylon ''Dalbergia melanoxylon'' (African blackwood, grenadilla, or mpingo) is a flowering plant in the family Fabaceae, native to seasonally dry regions of Africa from Senegal east to Eritrea and south to the north-eastern parts of South Africa. The ...

'' (African monkeywood). 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 heart-wood

Cultivation

''Laburnum''

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

and

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

s are cultivated as

ornamental trees Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that i ...

for gardens and parks. They are also trained as

espalier Espalier ( or ) is the horticultural and ancient agricultural practice of controlling woody plant growth for the production of fruit, by pruning and tying branches to a frame. Plants are frequently shaped in formal patterns, flat against a struct ...

s on

pergola A pergola is most commonly an outdoor garden feature forming a shaded walkway, passageway, or sitting area of vertical posts or pillars that usually support cross-beams and a sturdy open lattice, often upon which woody vines are trained. The ...

s, 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. 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 Oceanic may refer to: *Of or relating to the ocean *Of or relating to Oceania **Oceanic climate **Oceanic languages **Oceanic person or people, also called "Pacific Islander(s)" Places * Oceanic, British Columbia, a settlement on Smith Island, ...

climates like those of the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...

and

Northern Europe The northern region of Europe has several definitions. A restrictive definition may describe Northern Europe as being roughly north of the southern coast of the Baltic Sea, which is about 54th parallel north, 54°N, or may be based on other g ...

. ''Laburnum'' trees are ubiquitous in

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...

and

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

, 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 The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

References

External links

Flora Europaea: ''Laburnum''

ILDIS Legume Database

Laburnum tree video
— ''time lapse of a year in the life of a Laburnum tree''.

{{Taxonbar, from=Q147184 Genisteae Fabaceae genera Trees of Europe Flora of Europe Flora of Italy Garden plants of Europe Ornamental trees