The Annual Red Disa Pilgrimage: A Fern Encounter
It was time for the pilgrimage. As everyone knows, any even slightly botanical wonk in the Western Cape is required, in January and February, to undertake an arduous mountain hike into a kloof containing an appropriate patch of Afrotemperate forest, locate a wet, more or less south facing, vegetated cliff face and do homage to the icon of Western Cape flora that blooms there at this time of year, the lovely Disa uniflora.
The infirm may, in special circumstances, be exempt. Others, however, who fail to observe this sacred rite, are summarily condemned to twelve months of regret and self recrimination, the agony of which is assuaged only to a small degree by performing a daily penance throughout the remainder of the year by solemnly resolving not to miss the pilgrimage next time around.
And so it came to pass. The party toiled over stones, crossed the mountain stream several times, rested beside waterfalls, climbed ladders and, sure enough, Disa uniflora was there, high up beside the highest waterfall of them all. A serene sense of ‘duty done’ came over the party and we settled down to snacks and tea.
But it wasn’t all about Disa uniflora and Southern Afrotemperate forest isn’t all about trees. Ferns there are, aplenty. Paying attention to them is worth the trouble.
The large Grape fern, Todea barbara, is often thought to be a tree fern, but it’s not. Abundant in Leopard’s Kloof, it reminds us of the supercontinent Gondwana since it also occurs naturally in Australia and New Zealand.
The Seven-Weeks or Knysna fern, Rumohra adiantiformis has a strange property for a fern. Its specific name refers to its ability to cause water to run off its leaves, leaving them quite dry. It sports remarkably pronounced structures called sori (singular: sorus), containing spore bearing sporangia, on the underside of the leaf lobes.
Coral fern has a more descriptive Afrikaans common name, ‘Ystervaring’ (Iron fern), which evokes its tough wiry texture. Its scientific name takes a bit of practice, Gleichenia polypodioides. Best not to try that after a second glass of cabernet. A prolific climber, it prefers a rocky habitat. There’s a splendid display beside the path as you cross the Boekenhout Bridge on the way to the Disa Kloof waterfall in the Harold Porter National Botanical Gardens – which we visited after our Disa uniflora adventure in Leopard’s Kloof.
The broad fronds of Deerfern, Blechnum capense, aka Palm leaf fern, make it look like a wannabe cycad, except for its softer texture. Interestingly, it has two kinds of fronds, fertile and infertile. The fertile fronds are narrower and more widely spaced.
Okay, it’s time to give credit where credit is due. Yes, bracken is indeed a self respecting, globally distributed fern with the scientific name Pteridium aquilinum. The father of modern taxonomy, Carl Linnaeus, believed he could see the likeness of an eagle’s wings in a cross section of its roots, hence the Latin name, which roughly means ‘wings of an eagle’. Others argue that it’s the fronds that are reminiscent of eagles’ wings. So be it. It’s a notoriously opportunistic and widespread plant, aided by the extreme lightness of its wind dispersed spores. Despite its known toxicity, it contains carcinogenic ptaquiloside, it is eaten as a vegetable in Korea, Japan and China – after soaking in cold water, boiling and adding salt and baking soda to denature the toxin. Rather stick to spinach.
On the way back to the cars, spare a thought for the Assegaai trees, Curtisia dentata, beside the path, with their large, shiny, toothed leaves. They are Near Threatened, having suffered extensive logging for their hard and durable wood from the mid 17th to early 20th centuries. Today extensive bark stripping for the muti market adds to the threat. We may be inclined to take them for granted given their apparent abundance in our neck of the woods, but appearances can be deceiving. The species Curtisia dentata has the genus Curtisia and family Curtisiaceae all to itself . Its closes relatives belong to the order Cornales – the dogwoods of the Northern Hemisphere.
After a morning walk dedicated to the viewing of the notorious Disa
Uniflora, it was refreshing to encounter and admire the the often under apprecieated Fern.
But now it’s time to go home for lunch.
Author – Tim Attwell