Protea () is a genus of South African flowering plants, also called sugarbushes (Afrikaans: suikerbos). It is the type genus of the Proteaceae family.
About 92% of the species occur only in the Cape Floristic Region, a narrow belt of mountainous coastal land from Clanwilliam to Grahamstown, South Africa. Most protea species are found south of the Limpopo River. Protea madiensis grows in Afromontane enclaves across tropical Africa, from Guinea to Sudan, Mozambique, and Angola. Protea afra ranges from the Cape region to Uganda and Kenya, including in the chaparral zone of Mount 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.
Etymology
The genus Protea was named in 1735 by Carl Linnaeus when he was examining male and female plants of a species now known as Leucadendron 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 god Proteus who could change his form at will. Linnaeus's genus was formed by merging several genera previously published by Herman Boerhaave, although precisely which of Boerhaave's genera were included in Linnaeus's Protea varied with each of Linnaeus's publications.
Taxonomy
thumb|[[Protea eximia flower.]]
The family Proteaceae to which Protea species belong is an ancient one among angiosperms. Evidence from pollen fossils suggests Proteaceae ancestors grew in Gondwana, in the Upper Cretaceous, 75–80 million years ago. The Proteaceae are divided into two subfamilies: the Proteoideae, best represented in southern Africa, and the Grevilleoideae, 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 with Madagascar, whereas South America and Australia share many common genera – this indicates they separated from Africa before they separated from each other.
Description
Proteas usually flower during spring. Protea flowers have large heads made of small florets packed on a woody receptacle, each floret is reddish or pinkish in color and measures between 28.4 and 53.8 millimeters. The carpel in the flower's center is cream colored. The ovary is protected by the receptacle, and thus is not seen when looking at the flower, but the anthers 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.
- Cover the inflorescence, which contain only closed flowers, with a plastic bag
- Once the first few flowers have opened, most have to be cut back to 10-20 flowers around the receptacle
- After 3 days, the pollen may be applied using a toothpick. The flower should then again be covered with a plastic bag and marked with a tag containing information regarding the seed, the parent, and the date of pollination. This step should be repeated until all the flowers are opened and pollinated.
- The seed head should be harvested at 9-12 months and dried at temperatures more or less at 40°C to remove the seeds from the receptacle
- The seeds can be germinated in autumn using hot water
- The seeds should then be placed in a sterilized potting medium for germination.
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Genetics
The common Proteaceae plants, e.g. Protea, Leucospermum, and Leucadendron 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 with Leucospermum species because of the difference in their haploid chromosome number (13 and 12, respectively). This genetic 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.
<!--how-to Proteas are used for ornamental practices as cut flowers and for decoration, so some of the desirable traits a breeder is looking for during cultivation are flower size and colour etc. traits considered by breeders in the selection process for cultivation are long lasting bloom, flowering time, plant architecture, general appearance and adaptability. There are four main methods of selecting Protea flowers for further cultivation: Mass selection, Single plant clonal selection, Chance interspecific hybrid selection, Controlled-pollination interspecific hybrid selection.
--><!-- how-to The four main methods for cultivating Protea plants are sexual reproduction (cultivation with seed). When Proteas are cultivated using seeds, the first step in the cultivation process is to disinfect the seeds by soaking in water maintained at 50 °C for 30 minutes. The germination of the seeds will occur over a period of 14 to 28 days. The germinating seeds should be planted in a medium in pots before the developing roots are 10mm long. Another method for cultivation is vegetative propagation (cultivation with cuttings), which is used to obtain a large protea population of the same genotype. This cultivation method allows for the cultivation of hybrid protea plants without the loss of their unique characteristics. The other two cultivation methods include grafting and budding and micropropagation, referring to cultivation with tissue culture.
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Botanical history
Proteas attracted the attention of botanists visiting the Cape 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.
Cultivation
Proteas are currently cultivated in over 20 countries. Cultivation is restricted to Mediterranean and subtropical climates. 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. The cultivation of a Protea plant is time-consuming, so good planning when developing the cross combinations and goals are of great importance of the breeding programme. Another common hybrid is the Protea emixia which is cultivated to flower during the spring and summer months and thus provides cut flowers for export to the Northern Hemisphere.-->
References
External links
- Protea Atlas Project: a project to map the distribution of South African plant species, using Protea as a flagship.
- ncbi.nlm.nih.gov/Taxonomy/Browser
- Photographs of flowers from many species of Protea