At relatively short notice we were asked by two groups of botanists from Gauteng to show them certain taxa in the grasslands and forests along the Umtamvuna River,
The first was a group from the University of Pretoria who are investigating the possible effect of an Invasive Alien rust on indigenous Myrtaceae. We set off in search of the Eugenia species growing in our forests and forest fringes. Inspection of this genus in a local nursery had revealed significant infestation and they wanted to check whether the infestations have reached natural populations as well. Unfortunately this is indeed the case. While Eugenia erythrophylla (NT) and E. umtamvunensis (EN) both show signs of the rust, both on new and old leaves, E. verdoorniae seems to be more vulnerable and we found a number of fairly old trees which had suffered significant die-back. It is possible this rust (and perhaps in combination with other environmental factors) may sufficiently stress plants to cause them to die altogether. This is a great concern as all three of these species are endemic to our area. We will have to monitor the health of our populations.
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| Dieback on Eugenia verdoorniae |
Interestingly, it seems that the genus Syzygium has not yet been affected by this rust.
Other plants of interest encountered while searching for Eugenia trees were Streptocarpus porphyrostachys (NT) and Mystacidium aliceae (VU).
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| Streptocarpus porphyrostachys |
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| Mystacidium aliceae |
Participants: Anne S, Dorothy M, Graham G, Kate G, Maggie A, Uschi T, from CREW and Alisteir M, Esna duP, Jolanda R, Stewart F, from UP.
In the afternoon we were joined by a team from SANBI Pretoria who were on their way back to Pretoria after a protracted field trip and who were keen to see an unknown species of Aspidoglossum we recently encountered in the grassland at Cubica Heights. We were lucky enough to find several of these unobtrusive plants and Pieter Bester has undertaken to give us an ID next week once he gets back to Pretoria.
While out in the grassland we were able to show them other Apocynaceae in flower, namely Cryptocarya capensis and Riocreuxia torulosa, and finally a rather splendid specimen of Xysmalobium orbiculare.
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| Riocreuxia torulosa |
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| Xysmalobium orbiculare |
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| The Aspidoglossum hunters |
Participants: Anne S, Dorothy M, Graham G, Kate G, Maggie A, Uschi T, from CREW and Hester, S, Marinda K, and Pieter B from SANBI.
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