''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 (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the family Proteaceae,

endemic Endemism is the state of a species being found only 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 foun ...

to the Cape Provinces and

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN) is a Provinces of South Africa, province of South Africa that was created in 1994 when the government merged the Zulu people, Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu language, Zulu) and ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

, where they are a prominent part of the fynbos ecoregion and vegetation type.

Description

Species in the genus ''Leucadendron'' are small trees or shrubs 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. The leaves 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 flowers are produced in dense

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

s at the branch tips; plants are dioecious, with separate male and female plants. The seed heads, or infructescences, of ''Leucadendron'' are woody cone-like structures. This gave rise to their generic common name cone-bush. The cones contain numerous

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s. The seed morphology is varied and reflects subgeneric groupings within the genus. A few such as the Silvertree, '' Leucadendron argenteum'' 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 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 of high quality cut flowers 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 ''Leucadendron''.

Species

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 is the cultivar 'Rosette', a hybrid between ''L. laureolum'' and ''L. elimense''. This interspecific hybrid is however completely sterile due to autopolyploidy 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's Award of Garden Merit.

References

External links

* {{Authority control Proteaceae genera Endemic flora of South Africa Flora of the Cape Provinces Flora of KwaZulu-Natal Fynbos Dioecious plants Taxa described in 1810 Taxa named by Robert Brown (botanist, born 1773)