Protea flowers are named for a Greek god who kept changing shape
Linnaeus named Protea after Proteus, the sea god who could take many forms, and the family lives up to it. Proteaceae run from ground-hugging shrubs to 40-metre forest trees, with blooms like the king protea, waratah and banksia so varied that botanists cannot write one simple key to identify them.
The family holds 83 genera and about 1,660 species, concentrated in the Southern Hemisphere, with Australia and South Africa the richest regions. Its closest relatives are surprising: plane trees and the sacred lotus share the same order, Proteales. Familiar members include Grevillea, Hakea, Banksia, and Macadamia, whose nuts are farmed commercially, while the Chilean hazel Gevuina is eaten on a smaller scale. Banksia in particular is a striking case of adaptive radiation, one lineage diversifying into many forms.
The name has layers. Linnaeus coined Protea in 1767, Antoine Laurent de Jussieu used Proteae for the family in 1789, and Robert Brown adapted it into Proteaceae. Lawrie Johnson and Barbara Briggs classified the genera in a 1975 monograph, later largely replaced by molecular work from Peter Weston and Nigel Barker in 2006, which set out five subfamilies.
What looks like one big flower is usually a pseudanthium, a dense head of many small flowers. Their parts come in fours, and the mechanics are ingenious. The style grows while its tip is still trapped inside a cup formed by the fused tepals, so it bends until the flower tube splits along a seam. The style end often acts as a pollen presenter, holding pollen out for visiting animals.
Below ground, many species grow proteoid roots, dense clusters of short roots and hairs formed in leaf litter during the growing season. They release carboxylates that free up phosphorus locked in poor soils, a key advantage in nutrient-starved landscapes. The same adaptation, though, leaves them highly vulnerable to dieback caused by Phytophthora. Some species resprout from swollen woody bases called lignotubers, and a few even flower from them through the soil.
Source: Proteaceae
