I spent the weekend doing some training for the Freedom Challenge (www.freedomchallenge.org.za) mountain bike race across South Africa. This 2300 km adventure through some of the remotest parts of the land requires a fair bit of carrying ones bike as there are not always rideable roads or tracks. So I was in the process of heaving my bike up a particularly steep slope on the eastern side of Swartkransberg when I literally stumbled upon this population of the parasitic plant Mystropetalon thomii (the aardroos – directly translated the “earth’s rose”).
The flowers you can see in the photo consist of dense spikes of red unisexual flowers, the females are on the lower part of the flowering spike and males on the upper parts. These flowers develop inside the underground part of the plant, before rupturing and surfacing. The seeds are dispersed by ants.
The underground part of the plant, which looks like a tuber, is wholly parasitic on the roots of members of the Protea family, in particular Protea and Leucadendron.
These underground parts have no roots or chlorophyl but rather extract food and water from the host plant. This species is found infrequently in groups from the Hex River mountains to the Cape Peninsula and eastwards to Riversdale.