– Tim Attwell

Botsoc Walk 15 October 2016

It was as we expected and much more. Twenty members and guests piled into high clearance vehicles at the Harold Porter National Botanical Gardens and set off for Kasteelkop Nek in the Kleinmond Mountain Nature Reserve. Today we would not be toiling up rocky mountain paths, but ambling down a jeep track to see Western Coastal Shale Band vegetation up close, interpreted for us by renowned botanist and botanical historian Dr John Rourke.

Starting at a spot with splendid views of fold upon fold of mountains in every direction, Dr Rourke immediately had us scrambling up a rocky sandstone outcrop to inspect, not Western Coastal Shale Band vegetation at first, but a venerable specimen of Erica plukenetii grown unusually large, its rocky location having shielded it from fire for decades.

The other purpose of this energetic start to our expedition was to gain a panoramic view of the shale band vegetation we would be exploring. The swathe of shale band vegetation was unmistakable. The fine-grained, clayey soil of the shale band retains moisture and nutrients far better than the coarse quartzitic soils that support sandstone fynbos. We could see clearly how the vegetation growing on the shale band was more verdant than the mountain sandstone fynbos above and below it.

Then we were off down the jeep track. Beginning, literally, from the ground up, our attention was drawn to the sticky, moist clay soil beside the road, ground to powder and compacted by massive glaciers over 400 million years ago to form the shale from which it is derived.

Protea cordata, quintessential shale band inhabitant, was everywhere. It derives its specific name from the heart shape of its leaves, but the leaves’ red venation looks for all the world like blood vessels too. It bears its flowers at ground level, like Protea scabra, also in abundant evidence, to be pollinated by rodents, especially the striped mouse, Rhabdomys pumilio. Protea lepicarpodendron, black bearded protea, stood proud above the shrubs and challenged us to tell them apart from that other black beard of clay slopes, Protea neriifolia. Tall hemiparasitic Thesium euphorbiodes likewise, made a spectacle of itself.

The shale band vegetation was interrupted at times by large bands of Protea compacta extending down the mountainside. Now this was a puzzle. P. compacta doesn’t belong in shale band vegetation, it prefers sandy soils. The explanation: landslides released in stormy weather cause Table Mountain sandstone derived soils to overlay or replace shale. Landslides, Dr Rourke explained, far from being destructive, contribute significantly to the development of habitats for plant communities to form that are entirely different from their near neighbours, contributing to the bewildering and wonderful diversity of fynbos. The bands of P. compacta tell the story of colossal landslides in ages past.

Pretty china flowers, Adenandra uniflora, elegant long stalked spiderheads, Serruria elongata, red legged Berzelia abrotanoides (rooibeentjies), the wispy sedge Tetraria bromoides and, surprisingly, Pillansia templemannii, which is supposed to flower only after fire. But the last fire in that area was years ago!

We didn’t take a tea break until the end, which we did down on the boardwalk overlooking the sea among a flowering of Pelargonium cucullatum.

Thank you Dr John Rourke, for a rich and rewarding morning.