To understand the origins of the Cape Floral Kingdom and fynbos one must go back at least to the great events of 65 million years ago, when the age of the dinosaurs and gymnosperms came to a calamitous end, and the age of flowering plants and mammals took over.
Kirstenbosch National Botanical Garden Map With Cities Photo Gallery
For much of the last 65 million years, moist tropical forests dominated the landscapes of what is now southern Africa. Many familiar genera such as Podocarpus, Protea, Araucaria, Casuarina and tropical families like Anacardiaceae, Caesalpiniaceae and Euphorbiaceae, plus many species of palm, are present in the fossil record of this period. The climate oscillated through these many millions of years, with the expansion and contraction of closed forests and more open vegetation formations. Big changes started to happen from about 16 million years ago, with the final separation of Antarctica from South America resulting in the Antarctic Circumpolar Current, and later, about 12 million years ago, the cold Benguela Current.
Even more significant were the northward migration of the African continent, the build-up of the Antarctic icecap, and the lowering, and subsequent rising, of the sea level – creating extensive coastal plains of sandy, leached soils and, in some places such as the Agulhas Plain, limestone. By five million years ago, drier and generally cooler conditions prevailed, with cool, wet winters, and warm, dry summers. Fires became a significant driving force in ecosystem dynamics, opening up the vegetation and introducing clear habitats into which new, rapidly speciating families such as grasses and daisies, as well as shrubs and geophytes, could compete with fire-sensitive forest species. As the role of fire increased, soil erosion intensified, and soils became impoverished, again providing new opportunities for plant diversification.
The four major groups within the fynbos are represented here by (from top to bottom): Cannomois grandis (Restionaceae), Leucospermum erubescens (Proteaceae), Erica regia (Ericaceae) and Sparaxis elegans (geophytes).
Floristically, fynbos is characterised by three families – Restionaceae, Proteaceae and Ericaceae, plus a vast array of species from other families, notably Iridaceae, that share a common strategy to survive the summer drought by having underground bulbs, corms or rhizomes – the so-called geophytes.
Restios – also called Cape reeds – are grass-like but with much reduced leaves, and are found in all fynbos communities, from the coastal shores to mountain peaks. Restios have been around for over 120 million years, and are also found in Australia. The fynbos is home to 314 species of restio – all with separate male and female plants.
A major contributor to the diversity of fynbos is that of the genus Erica – with 682 out of a global total of 816 species. No fewer than 104 species are to be found on the Cape Peninsula. Europe has just 14 species, of which only six occur in the much romanticised heathlands of Scotland. For several months of the year, ericas look drab, grey-green and monotonous, with very little diversity in growth form and dimension. But from spring to the end of autumn, at flowering, the swathes of colour over the mountains and plains – pinks and mauves and complex mixes of greens and yellows give a special serenity and tranquillity to the scene.