Leucadendron | |
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Leucadendron argenteum | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Order: | Proteales |
Family: | Proteaceae |
Subfamily: | Proteoideae |
Tribe: | Leucadendreae |
Subtribe: | Leucadendrinae |
Genus: | Leucadendron R.Br. |
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Natural range of the genus | |
Synonyms [1] | |
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Leucadendron is a genus of about 80 species of flowering plants in the family Proteaceae, endemic to the Cape Provinces and KwaZulu-Natal in South Africa, where they are a prominent part of the fynbos ecoregion and vegetation type. [1]
Species in the genus Leucadendron are small trees or shrubs that are erect or creeping. [2] 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 inflorescences 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 seeds. 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.
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. [3]
85 species are accepted. [1]
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. [4] The genus Leucadendron is popular amongst consumers due to its colourful bracts and long vase life. Leucadendron hybrids are produced through interspecific hybridization. [5] 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. [4]
In the UK the cultivars 'Safari Sunset' [6] and 'Inca Gold' [7] have gained the Royal Horticultural Society's Award of Garden Merit. [8]
Leucospermum commonly known as pincushions, is a genus of evergreen upright, sometimes creeping shrubs that is assigned to the Proteaceae, with currently 48 known species.
Hakea is a genus of about 150 species of flowering plants in the family Proteaceae, endemic to Australia. They are shrubs or small trees with leaves that are sometimes flat, otherwise circular in cross section in which case they are sometimes divided. The flowers are usually arranged in groups in leaf axils and resemble those of other genera, especially Grevillea. Hakeas have woody fruit which distinguishes them from grevilleas which have non-woody fruit which release the seeds as they mature. Hakeas are found in every state of Australia with the highest species diversity being found in the south west of Western Australia.
Isopogon, commonly known as conesticks, conebushes or coneflowers, is a genus of about forty species of flowering plants in the family Proteaceae, and are endemic to Australia. They are shrubs with rigid leaves, bisexual flowers in a dense spike or "cone" and the fruit is a small, hairy nut.
Petrophile is a genus of evergreen shrubs, in the family Proteaceae. The genus is endemic to Australia. Commonly known as conebushes, they typically have prickly, divided foliage and produce prominently-displayed pink, yellow or cream flowers followed by grey, conical fruits.
Mimetes, the pagoda, is a genus of evergreen shrubs or small trees 0.5–6 m (1.6–19.7 ft) high, with thirteen species assigned to the family Proteaceae. This genus, as with other proteas, is popular with nectarivorous birds such as the Cape sugarbird and several sunbird species. All species of Mimetes are endemic to the Cape Floristic Region of South Africa.
Serruria, or spiderhead is a genus of flowering plants in the family Proteaceae, endemic to South Africa.
Paranomus is a genus of 18 species of flowering plants, commonly known as "sceptres", in the protea family. It is endemic to the Cape Floristic Region of South Africa.
Spatalla is a genus containing 20 species of flowering plants, commonly known as "spoons", in the family Proteaceae. The genus is endemic to the Cape Floristic Region of South Africa where it is associated with fynbos habitats. The species are all small shrubs. The name is derived from the Greek, meaning “wantonness”, alluding to the plants’ unusually large pollen-presenters. Most species are threatened.
Diastella is a genus containing seven species of flowering plants, commonly known as “silkypuffs”, in the protea family. The name comes from the Greek diastellein “to separate”, with reference to the free perianth lobes – the plants are distinguished from the closely related and similar leucospermums by the possession of four free perianth segments. The genus is endemic to the Cape Floristic Region of South Africa where it has a very limited range and is associated with fynbos habitats. The species are all small shrubs. Most species are threatened.
Leucospermum oleifolium is an erect shrub of about 1 m (3.3 ft) high and 1½ m (5 ft) across that is assigned to the family Proteaceae. It has spreading branches, densely set with initially felty, entire, oval, olive-colored leaves of about 3½ cm long and 1½ cm (0.6 in) wide, with a bony tip that sometimes has two to five blunt teeth, with a blunt base and conspicuous veins. The flowers and their long thread-like styles are initially sulfur yellow, but soon become orange and finally turn brilliant crimson. The flower heads are about 4 cm (1.6 in) in diameter, crowded at the tip of the branches with a maximum of five that start flowering in turn. This provides for a colour spectacle from August till December. It is called by various names in South Africa such as Overberg pincushion, flame pincushion, mix pincushion and tuft pincushion. It naturally occurs in fynbos in the Western Cape province of South Africa.
Leucadendron thymifolium, the Malmesbury 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.
Leucadendron meyerianum, the Van Rhynsdorp conebush, is a flower-bearing shrub that belongs to the family Proteaceae. It is part of the fynbos vegetation type of South Africa. The plant is native to the Western Cape and Northern Cape, where it occurs in the Bokkeveld escarpment near Nieuwoudtville. The shrub grows 2.0 m tall and bears flowers in August. Two months after the plant has flowered, the fruit appears and the seeds later fall to the ground where they are spread by rodents. The plant grows in level, sandstone sand at altitudes of 800 m. Small beetles do the pollination.