Greetings fellow Foxies,
I became interested in Proteaceae via gravelly soils while working for the WA Department of Agriculture as an adviser. At that time it was thought that ancient fluctuating groundwater created gravel, and that Proteaceae evolved to grow on these soils.
Dr Bill Verboom (a work colleague), turned this idea on its head by proposing that plants can create soils to give them an evolutionary advantage. Proteaceae have evolved cluster roots, which enable them to access the nutrient phosphorus in infertile soils. Cluster roots and associated soil microbes create lateritic soils including bauxite. For more information click here.
I recently realised that I didn't know how to distinguish Proteaceae genera from each other. Alas my ageing memory is less than photographic, and I rely on rules of thumb. Here is my rough guide. No doubt there are exceptions but some may find it useful.
Proteaceae have tubular flowers (a corolla) with four tepals (combined petal/sepal).
The central female part consists of a superior (above surface of flower base) ovary connected to a single unbranched style.
Their fruit only has one or two seeds in a 2-lobed papery (Grevillea) or woody (Hakea, Lambertia) fruit or cone (Banksia, Isopogon or Petrophile, or tiny nuts (Conospermum, Synaphea, or drupes (Persoonia).
Most Proteaceae produce few seeds, particularly resprouters
Species with short corolla tube and small tepals
Species with a medium to long corolla tube - the style bursts out of the side of the tube before the tepals separate
Species with medium to long corolla tube - style emerges from end of corolla tube as tepals fold back