Laburnum
- "Indian laburnum" is the golden shower tree, a distant relative of the genus Laburnum.
| Laburnum | |
|---|---|
 | |
| Common laburnum – flowers | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Fabales |
| Family: | Fabaceae |
| Subfamily: | Faboideae |
| Tribe: | Genisteae |
| Genus: | Laburnum Fabr. |
| Species | |
Laburnum, commonly called golden chain, 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 Balkan Peninsula.
Some botanists include a third species, Laburnum caramanicum, but this native of southeast Europe and Asia Minor is usually treated in a distinct genus Podocytisus, more closely allied to the 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 (1.6–2.0 in) long in L. alpinum.
They have yellow pea-flowers in pendulous racemes 10–30 cm (4–12 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.
The yellow flowers are responsible for the old poetic name 'golden chain tree' (also spelled golden chaintree or goldenchain tree).
All parts of the plant are poisonous, and can be lethal if consumed in excess. 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 buff-tip.
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[1] before taste turned to imported dense tropical hardwoods such as cocuswood, ebony, and African blackwood.[2] The heart-wood of a laburnum may be used as a substitute for ebony or rosewood, very hard and a dark chocolate brown, with a butter-yellow sapwood.
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.
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.[3]
Cultural references
In the TV mystery series Mother Love, Helena (Diana Rigg) muses over what plant she should use to poison a pair of children and chooses the laburnum, saying, "Laburnum! Such a pretty tree – and so many of them!" In the Doctor Who serial "The Mark of the Rani", the Sixth Doctor suggests that if the Master turned into a tree, it would be a laburnum, because they have poisonous pods.
The novel A Melon for Ecstasy by John Fortune and John Wells is, in part, about the main character's forbidden love affair with the laburnum in his back yard. Laburnum seeds are the agent of suspected poisoning in the Daphne du Maurier novel My Cousin Rachel. In Wizardborn, the third book in Dave Wolverton's (David Farland} The Runelords series, Averan, the Earth Warden, chooses her staff of power from the wood of the laburnum tree. Laburnum also provides an important clue in the sixth series episode of the Inspector Lewis TV mystery series, "The Soul of Genius."
Laburnums are mentioned in J.R.R. Tolkien's The Hobbit by Bilbo to describe Gandalf's fireworks. They are also written about in The Lion, the Witch, and the Wardrobe by C.S. Lewis; they are mentioned when the snow is melting, showing the White Witch's spell is breaking.
References
- ↑ B. J. Rendle (March 1969). World Timbers: Europe and Africa. E. Benn. p. 40. Retrieved 29 April 2011.
- ↑ Joshua Dickson (9 October 2009). The Highland bagpipe: music, history, tradition. Ashgate Publishing, Ltd. pp. 50–. ISBN 978-0-7546-6669-1. Retrieved 29 April 2011.
- ↑ "RHS Plant Selector - Laburnum × watereri 'Vossii'". Royal Horticultural Society. Retrieved 20 May 2013.
 |
Wikimedia Commons has media related to Laburnum. |
External links
- Flora Europaea: Laburnum
- ILDIS Legume Database
- Laburnum tree video — time lapse of a year in the life of a Laburnum tree.