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

horticultural Horticulture (from ) is the art and science of growing fruits, vegetables, flowers, trees, shrubs and ornamental plants. Horticulture is commonly associated with the more professional and technical aspects of plant cultivation on a smaller and mo ...

curiosity; a small tree which is a graft-chimaera 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 ''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 ...

'', and a

broom A broom (also known 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. It is thus a ...

, '' 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 The plus sign () and the minus sign () are mathematical symbols used to denote positive and negative functions, respectively. In addition, the symbol represents the operation of addition, which results in a sum, while the symbol represents ...

(+) 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 Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...

, 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 Fabaceae () or Leguminosae,International Code of Nomen ...

). Only one

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

, '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 Cultivate ...

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 Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s in late spring or early summer; some branches have long (20–30 cm)

raceme A raceme () or racemoid is an unbranched, indeterminate growth, 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 ...

s 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 Hardy may refer to: People * Hardy (surname) * Hardy (given name) * Hardy (singer), American singer-songwriter Places Antarctica * Mount Hardy, Enderby Land * Hardy Cove, Greenwich Island * Hardy Rocks, Biscoe Islands Australia * Hardy, ...

to USDA plant hardiness zone 5 in northern

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

. 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 city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

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 horticulture, 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 roots ...

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 ...

. 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 diff ...

but a mixture of

cells Cell most often refers to: * Cell (biology), the functional basic unit of life * Cellphone, a phone connected to a cellular network * Clandestine cell, a penetration-resistant form of a secret or outlawed organization * Electrochemical cell, a d ...

, each with the

genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...

of one of its "parents"; it is a

chimaera Chimaeras are Chondrichthyes, cartilaginous fish in the order (biology), order Chimaeriformes (), known informally as ghost sharks, rat fish (not to be confused with rattails), spookfish, or rabbit fish; the last two names are also applied to B ...

, 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 ''Crataegus'' (), commonly called hawthorn, quickthorn, thornapple, Voss, E. G. 1985. ''Michigan Flora: A guide to the identification and occurrence of the native and naturalized seed-plants of the state. Part II: Dicots (Saururaceae–Cornacea ...

'') and medlar (''

Mespilus ''Mespilus'', commonly called medlar, is a 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 Albanian, Ma ...

'') 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

Bizzarria Bizzarria 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 leave ...

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

sour orange The bitter orange, sour orange, Seville orange, bigarade orange, or marmalade orange is the hybrid citrus tree species ''Citrus'' × ''aurantium'', and its fruit. It is native to Southeast Asia and has been spread by humans to many parts of th ...

References

External links

* {{DEFAULTSORT:Laburnocytisus adamii Genisteae Graft chimeras