Protea (/ˈproʊtiːə/ 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.
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.
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. Some protea flower species, like the king protea flower, are self-pollinating flowers. Other protea species, however, such as P. cordata, P. decurrens, and P. scabra are self-incompatible, and thus rely on cross-pollination for successive seed sets. Some Protea 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.
