''Leucadendron'' is a genus of about 80 species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants t ...

s in the family

Proteaceae The Proteaceae form a family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genera with about 1,660 known species. Together with the Platanaceae and Nelumbonaceae, they make up the order ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...

, where they are a prominent part of the

fynbos Fynbos (; meaning fine plants) is a small belt of natural shrubland or heathland vegetation located in the Western Cape and Eastern Cape provinces of South Africa. This area is predominantly coastal and mountainous, with a Mediterranean clim ...

ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of ...

and vegetation type.

Description

Species in the genus ''Leucadendron'' are 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 or

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...

s that are erect or creeping. Most species are shrubs that grow up to 1 m tall, some to 2 or 3 m. A few grow into moderate-sized trees up to 16 m tall. All are

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

. The

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

are largely elliptical, sometimes needle-like, spirally arranged, simple, entire, and usually green, often covered with a waxy bloom, and in the case of the Silvertree, with a distinct silvery tone produced by dense, straight, silky hairs. This inspired the generic name ''Leucadendron'', which literally means "white tree". The

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 mechanis ...

s are produced in dense

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...

s at the branch tips; plants are

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproducti ...

, with separate male and female plants. The seed heads, or

infructescence Infructescence (fruiting head) is defined as the ensemble of fruits derived from the ovaries of an inflorescence. It usually retains the size and structure of the inflorescence. In some cases, infructescences are similar in appearance to simple fru ...

s, of ''Leucadendron'' are woody cone-like structures. This gave rise to their generic common name cone-bush. The cones contain numerous

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

s. The seed morphology is varied and reflects subgeneric groupings within the genus. A few such as the Silvertree, ''

Leucadendron argenteum ''Leucadendron argenteum'' (silver tree, silver leaf tree, af, Witteboom, or af, Silwerboom) is an endangered plant species in the family Proteaceae, which is endemic to a small area of the Cape Peninsula, South Africa. Most grow in and around ...

'' have a silky-haired parachute, enabling the large round nut to be dispersed by wind. A few are rodent dispersed, cached by rats, and a few have elaiosomes and are dispersed by ants. About half the species store the seeds in fire-proof cones and release them only after a fire has killed the plant or at least the branch bearing the cone. Many such species hardly recruit naturally except after fires.

Cultivation

''Leucadendron'' plants are conventionally propagated through seedlings as well as cuttings. The seeds reach maturity over a duration of a year. This time of germination and emergence depends on the species. When using cuttings as propagating material, the season as well as the type of material used can affect the success rate of the cultivation. Cuttings are preferred as propagating material because it provides uniform offspring, whereas seedlings produce genetic variability in the offspring. The genus ''Leucadendron'' is more prone to

genetic variation Genetic variation is the difference in DNA among individuals or the differences between populations. The multiple sources of genetic variation include mutation and genetic recombination. Mutations are the ultimate sources of genetic variation, b ...

than a genus that tends to self-fertilize, because of its cross-pollinating nature. In the natural habitat, ''Leucadendron'' grows exceptionally well, but in the case of cultivation the specific needs of the plant have to be readily available to allow optimal production to produce high quality

cut flowers Cut flowers are flowers or flower buds (often with some stem and leaf) that have been cut from the plant bearing it. It is usually removed from the plant for decorative use. Typical uses are in vase displays, wreaths and garlands. Many garde ...

and foliage. Steps for cultivation include soil evaluation, clearing, drainage, chemical correction, and the physical preparation should be critically considered five months prior to planting ''Leucadendrons''. The selection criteria for cultivating ''Leucadendron'' species is of great importance and should be based on the agricultural ability of the plant as well as the current market standards.

Selected species

*''

Leucadendron album ''Leucadendron album'' is a species of flowering plant in the family Proteaceae that grows in South Africa. Gallery Leucadendron album 15319583.jpg Leucadendron album 15319586.jpg Leucadendron album 62521390.jpg Leucadendron album 65607987.j ...

'' *''

Leucadendron arcuatum ''Leucadendron arcuatum'', the red-edge conebush, is a flower-bearing shrub that belongs to the genus ''Leucadendron'' and forms part of the fynbos. The plant is native to the Western Cape, South Africa. Description The shrub grows tall and be ...

'' *''

Leucadendron barkerae ''Leucadendron barkerae'', the Swartberg conebush, is a flower-bearing shrub that belongs to the genus ''Leucadendron'' and forms part of the fynbos. The plant is native to the Western Cape, South Africa. Description The shrub grows tall and b ...

'' *''

Leucadendron bonum ''Leucadendron bonum'', the Gideonskop conebush, is a flower-bearing shrub that belongs to the genus '' Leucadendron'' and forms part of the fynbos. The plant is native to the Western Cape, South Africa South Africa, officially the Repub ...

'' *''

Leucadendron brunioides ''Leucadendron brunioides'', the foetid conebush, is a species of plant in the family Proteaceae. It was first described in 1856 by Carl Meissner. Description ''Leucadendron brunioides'' is endemic to sandy flats and shrublands of South Africa ...

'' *''

Leucadendron burchellii ''Leucadendron burchellii'', the Riviersonderend conebush, is a flower-bearing shrub that belongs to the genus ''Leucadendron'' and forms part of the fynbos. The plant is native to the Western Cape, South Africa. Description The shrub grows tal ...

'' *''

Leucadendron cadens ''Leucadendron cadens'', the Witteberg sunbush, is a flower-bearing shrub that belongs to the genus ''Leucadendron'' and forms part of the fynbos. The plant is native to the Western Cape, South Africa. The plant is rare. Description The plant ...

'' *''

Leucadendron chamelaea ''Leucadendron chamelaea'', the Witsenberg conebush, is a flower-bearing shrub that belongs to the genus ''Leucadendron'' and forms part of the fynbos. The plant is native to the Western Cape, South Africa. Description The shrub grows tall and ...

'' *''

Leucadendron cinereum ''Leucadendron cinereum'', the scraggly conebush, is a flower-bearing shrub that belongs to the genus ''Leucadendron'' and forms part of the fynbos. The plant is native to the Western Cape where it occurs from Hopefield and on the Cape Flats fro ...

Leucadendron meridianum ''Leucadendron meridianum'', the limestone conebush, is a flower-bearing shrub belonging to the genus ''Leucadendron'' and forms part of the fynbos. The plant is native to the Western Cape, South Africa. Description The shrub grows tall an ...

'' *'' Leucadendron meyerianum'' *''

Leucadendron microcephalum ''Leucadendron microcephalum'', common name oilbract conebrush, is a dioecious, single-stemmed, South African shrub belonging to the family Proteaceae, endemic to the Western Cape and growing from sea level to . It is one of some 200 species ...

'' *'' Leucadendron modestum'' *'' Leucadendron muirii'' *'' Leucadendron nervosum'' *'' Leucadendron nitidum'' *'' Leucadendron nobile'' *'' Leucadendron olens'' *'' Leucadendron orientale'' *'' Leucadendron osbornei'' *'' Leucadendron platyspermum'' *''

Leucadendron pondoense ''Leucadendron pondoense'', the Pondoland conebush, is a flower-bearing shrub that belongs to the genus '' Leucadendron'' and forms part of the fynbos. The plant is native to the Eastern Cape where it occurs in the Pondoland from Port St. Johns ...

'' *''

Leucadendron procerum ''Leucadendron procerum'', the ivory conebush, is a flower-bearing shrub that belongs to the genus ''Leucadendron'' and forms part of the fynbos. The plant is native to the Western Cape, South Africa. Description The shrub grows tall and ...

Leucadendron thymifolium ''Leucadendron'' is a genus of about 80 species of flowering plants in the family Proteaceae, endemic to South Africa, where they are a prominent part of the fynbos ecoregion and vegetation type. Description Species in the genus ''Leucadendron' ...

'' *'' Leucadendron tinctum'' *'' Leucadendron tradouwense'' *'' Leucadendron uliginosum'' *'' Leucadendron verticillatum'' *'' Leucadendron xanthoconus''

Hybridization

The drive behind the production of new ''Leucadendron'' cultivars is the production of a constant supply of new and improved quality products that are available initially from South Africa only. The genus ''Leucadendron'' is popular amongst consumers due to its colourful bracts and long vase life. ''Leucadendron'' hybrids are produced through interspecific hybridization. Crosses made within the same subsection are generally more viable in the hybridization of ''Leucadendrons'' with the quantity of seed set relative to the taxonomic relatedness of the species. Intersectional hybridization produces hybrids that show a unique set of characteristics which are favoured by consumers. One example of a hybrid produced by two ''Leucadendron''

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

is the cultivar ‘Rosette’, a hybrid between ''L. laureolum'' and ''L. elimense''. This interspecific hybrid is however completely sterile due to

autopolyploidy Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set conta ...

and thus have no use in further cultivation. The main aim of interspecific hybridization is to produce large quantities of progeny seed from the best interspecific hybrid parents. In the UK the cultivars ‘Safari Sunset’ and ‘Inca Gold’ have 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 (Nor ...

’s

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

* {{Taxonbar, from=Q159466 Proteaceae genera Endemic flora of South Africa Flora of the Cape Provinces Fynbos Dioecious plants