| Protea | |
|---|---|
 | |
| The original South African "suikerbossie" (sugarbush)Protea repens | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Proteales |
| Family: | Proteaceae |
| Subfamily: | Proteoideae |
| Tribe: | Proteeae |
| Genus: | Protea L. (1771), nom. cons. |
| Species | |
| Synonyms[1] | |
| |
Protea (/ˈproʊtiːə/[2]) is agenus of South Africanflowering plants, also calledsugarbushes (Afrikaans:suikerbos). It is thetype genus of theProteaceae family.[3]
About 92% of the species occur only in theCape Floristic Region, a narrow belt of mountainous coastal land fromClanwilliam toGrahamstown, South Africa. Most protea species are found south of theLimpopo River.Protea madiensis grows inAfromontane enclaves across tropical Africa, fromGuinea toSudan,Mozambique, andAngola.[4]Protea afra ranges from the Cape region toUganda andKenya, including in thechaparral zone ofMount Kenya National Park. The extraordinary richness and diversity of species characteristic of the Cape flora are thought to be caused in part by the diverse landscape, where populations can become isolated from each other and in time develop into separate species.
The genusProtea was named in 1735 byCarl Linnaeus when he was examining male and female plants of a species now known asLeucadendron argenteum which are very different from each other; he misunderstood them to be two different species, and he compared those forms to the ability of Greek godProteus who could change his form at will.[5][6] Linnaeus's genus was formed by merging several genera previously published byHerman Boerhaave, although precisely which of Boerhaave's genera were included in Linnaeus'sProtea varied with each of Linnaeus's publications.
The familyProteaceae to whichProtea species belong is an ancient one amongangiosperms. Evidence from pollen fossils suggests Proteaceae ancestors grew inGondwana, in theUpper Cretaceous, 75–80 million years ago.[7] The Proteaceae are divided into two subfamilies: theProteoideae, best represented in southern Africa, and theGrevilleoideae, concentrated in Australia and South America and the other smaller segments of Gondwana that are now part of eastern Asia. Africa shares only one genus withMadagascar, whereasSouth America and Australia share many common genera – this indicates they separated from Africa before they separated from each other.
Proteas usually flower during spring. Protea flowers have largeheads made of small florets packed on a woodyreceptacle, each floret is reddish or pinkish in color and measures between 28.4 and 53.8 millimeters. Thecarpel in the flower's center is cream colored.[8] Theovary is protected by the receptacle, and thus is not seen when looking at the flower, but theanthers are present at the top of the flower, which can then easily transfer the pollen to the vectors.
Proteas are pollinated by birds, insects, and wind. All the florets open big enough for small and medium beetles to land and feed on their nectar before flying to other heads pollinating them in the process.[8] Some protea flower species, like theking protea flower, areself-pollinating flowers. Other protea species, however, such asP. cordata,P. decurrens, andP. scabra areself-incompatible, and thus rely on cross-pollination for successive seed sets. SomeProtea species exhibit both self-pollination and cross-pollination as a method of reproduction. Cross-pollination is preferred, though, as a method of reproduction because it provides genetic diversity in the population. When cultivating proteas, breeders use hand pollination as a controlled method to transfer pollen from one flower to another.
The common Proteaceae plants, e.g.Protea,Leucospermum, andLeucadendron are diploid organisms, thus they can freely hybridize with closely related species to form new cultivars. Unusually, not all the genera within the family Proteaceae can hybridize freely; for example,Leucadendron species cannot be crossed withLeucospermum species because of the difference in their haploid chromosome number (13 and 12, respectively). Thisgenetic incompatibility results in pollinated flowers that yield either no fruit, or seedless fruit, as the resulting plant embryos, from the incompatible pollen and ovum, fail to develop.
Proteas attracted the attention of botanists visiting theCape of Good Hope in the 17th century. Many species were introduced to Europe in the 18th century, enjoying a unique popularity at the time amongst botanists.
Proteas are currently cultivated in over 20 countries. Cultivation is restricted to Mediterranean andsubtropical climates.[9] Three categories of traits have to be considered before developing a new cultivar. The yield or production capacity of the cultivar must be considered. The ease of handling and packaging of the cut stems and the last category is to consider the perceived market value of the cultivar.[10] The cultivation of aProteaplant is time-consuming, so good planning when developing the cross combinations and goals are of great importance of the breeding programme.[10]
Within the huge familyProteaceae, they are a member of the subfamily Proteoideae, which has Southern African and Australian members.
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(listed by section: a 'section' has a name in two parts, consisting of the genus name and an epithet).
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