+'' Laburnocytisus'' 'Adamii' (also known as Adam's laburnum or broom laburnum) is a

horticultural Horticulture is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and no ...

curiosity; a small tree which is 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 ...

between two species, a

laburnum ''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''� ...

, '' Laburnum anagyroides'', and a

broom A broom (also known in some forms as a broomstick) is a cleaning tool consisting of usually stiff fibers (often made of materials such as plastic, hair, or corn husks) attached to, and roughly parallel to, a cylindrical handle, the broomstick. I ...

, '' Chamaecytisus purpureus'' ( syn. ''Cytisus purpureus''), which bears some shoots typical of the one species, some of the other, and some which are a peculiar mixture of both "parents". The plus sign (+) indicates the generic name is made for a graft-chimaera. The plant can also be described by the formula ''Laburnum anagyroides'' + ''Chamaecytisus purpureus''. + ''Laburnocytisus'' 'Adamii' is a

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...

, a member of the pea family

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 widely ...

(or

Papilionaceae 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 widely ...

, formerly Leguminosae). Only one

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

, 'Adamii' is known to have arisen from this graft. It is sometimes described as if it were one species, (+ )''Laburnocytisus adamii''; however, it is not one species and this notation is not conforming to

International Code of Nomenclature for Cultivated Plants The ''International Code of Nomenclature for Cultivated Plants'' (ICNCP), is a guide to the rules and regulations for naming cultigens, plants whose origin or selection is primarily due to intentional human activity. It is also known as Cultivat ...

Appearance

Most of the tree's branches resemble the laburnum in their foliage, which has three leaflets ( 3-palmate) and 3–6 cm long, yet also with dense clusters of broom-like shoots, also with three leaflets, but only 1 cm long and a darker green. It

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 late spring or early summer; some branches have long (20–30 cm) racemes of yellow laburnum flowers, while others produce dense clusters of purple broom flowers. Remarkably, most branches will also produce coppery-pink flowers on short (8–15 cm) racemes, which are midway between the two "parents"; the leaves on these shoots are also intermediate. In older specimens, the proportion of broom and mixed tissues tends to decline, and the laburnum to predominate. The tree grows to a height of 7 m (rarely 8 m) and is hardy to USDA plant hardiness zone 5 in northern

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 ...

. It requires moderately fertile, moist but well-drained soil and should be grown in a sunny position to flower well.

Origin

The plant originated in the nursery of M. Adam near

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...

in 1825, probably as an accident;''Hillier's Manual of Trees & Shrubs'' 5th Edition (1984) 164. ''Chamaecytisus purpureus'' is normally a low-growing plant, and

grafting Grafting or graftage is a horticultural technique whereby tissues of plants are joined so as to continue their growth together. The upper part of the combined plant is called the scion () while the lower part is called the rootstock. The succ ...

it onto a straight trunk of a related species would be expected to create an attractive, semi-weeping

standard Standard may refer to: Symbols * Colours, standards and guidons, kinds of military signs * Standard (emblem), a type of a large symbol or emblem used for identification Norms, conventions or requirements * Standard (metrology), an object th ...

. In theory, other + ''Laburnocytisus'' could be developed in the same way but using different "parents".

Structure

A graft-chimaera is not a true

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 ...

but a mixture of cells, each with the genotype of one of its "parents"; it is a chimaera, created by grafting, in which the tissue of one plant grows within an outer envelope of the second plant. In the case of + ''Laburnocytisus'' 'Adamii', laburnum forms the core, surrounded by the broom. Such plants are often called "graft hybrids", but as they are not true hybrids the use of this term is now discouraged.

Other graft-chimaeras

+ ''Crataegomespilus'' is a graft-chimera between hawthorn ('' Crataegus'') and medlar (''

Mespilus ''Mespilus'', commonly called medlar, is a monotypic genus of flowering plants in the family Rosaceae containing the single species ''Mespilus germanica'' of southwest Asia. It is also found in some countries in the Balkans, especially in Alb ...

'') which arose in a similar manner. There are two distinct

s that have arisen from this graft: + ''Crataegomespilus'' 'Dardarii' and + ''Crataegomespilus'' 'Jules d'Asnieres'.''RHS Plant Finder 2006–2007'' 20th Edition (2006) 202. The

Bizzaria The Bizzaria of Florence (''Citrus medica'' + ''C. aurantium''), which is probably the first graft chimera obtained, is a graft between the Florentine citron and sour orange. It produces branches of regular Florentine citron including such le ...

of Florence (''Citrus medica'' + ''C. aurantium''), which is probably the first graft chimera obtained, is a graft between the

Florentine citron The Florentine citron – citron hybrid of Florence ( it, cedrato di Firenze) – is a very fragrant citrus fruit, which is named after its most known origin of cultivation. Its scientific name is ''Citrus × limonimedica'' 'Florentina' Lush. ...

and

sour orange Bitter orange, Seville orange, bigarade orange, or marmalade orange is the citrus tree ''Citrus'' × ''aurantium'' and its fruit. It is native to Southeast Asia and has been spread by humans to many parts of the world. It is probably a cross bet ...

References

External links

* {{DEFAULTSORT:Laburnocytisus adamii Genisteae Graft chimeras