Note 9: New in Zimbabwe ... well, not quite! by Bart Wursten

The author describes the discovery at the Harare National Herbarium (SRGH) on 2 January 2009 of two specimens of Pyrenacantha kirkii, thus enabling this species to be added to the Zimbabwe flora.

Photo: One of the re-discovered specimens of Pyrenacantha kirkii, Ngoni 207.

Photo: The other re-discovered specimen of Pyrenacantha kirkii, Mueller and Pope 2022.

Zimbabwean botany is often still full of surprises and sometimes they come from unexpected directions.

In February 2007, I photographed a climber in the near-coastal forests of Central Mozambique, near the Chiniziuwa River, North of Beira.

It was quite a distinctive species with unusual leaves, some of which were almost diamond shaped, while others had 3 pointed apical lobes. It had a cluster of bright orange berry-like fruits and although the flowers were small and inconspicuous, the inflorescence was unusual with its stout peduncle and the flowers attached to what appeared to be a somewhat swollen rhachis.

I was excited and honoured to be in the company of experts such as John Burrows and Meg Coates Palgrave, but the identity of this species eluded us all.

After the trip, there was so much new material to identify and so much new knowledge to absorb, that the pictures of this obscure climber got stored away and forgotten until I recently stumbled across the photos by accident. They still had me completely stumped. Despite having pictures showing leaves, fruits and an inflorescence, I could not even think of what family the species would belong to. We tried Menispermaceae but could not find a single specimen at the herbarium that even remotely looked like our plants. Although there were no tendrils present, we searched through all the grapes and cucumbers (Vitaceae and Cucurbitaceae), predictably without any success.

In the end both Mark and I decided to resort to desparate measures: we simply browsed through each volume of the Flora Zambesiaca and every other botanical book in our library to see if anything would trigger some form of recognition.

I admit that this does not exactly qualify as the most professional form of botanical approach but hey, we had pretty much run out of options and anything so utterly unknown just had to be of interest.

Although we eventually came out of this exercise without too much hope of success, Mark had come up with a slight possibility in the form Pyrenacantha kirkii, an obscure climber from Mozambique in the family of Icacinaceae.

Another visit to the National Herbarium was in order to see if any specimens were present and, if so, would they possibly match the plant in our photographs.

Several specimens from Mozambique were indeed found but once again we seemed to be disappointed. The leaves in the specimens were all simply elliptic, without the distinct pointed lobes, and the inflorescences also looked quite different. We were about to give up when we saw another folder marked Zimbabwe: Eastern Division. This surely had to be a misfiled folder as Pyrenacantha kirkii is not listed as a Zimbabwean species. However, as soon as we opened the folder we could see we had found a perfect match: the same lobed leaves and the same distinct inflorescence.

As it turned out the leaves are quite variable and the Zimbabwean specimens just happened to be more similar. The flowers are unisexual with the sexes on different plants in rather different looking inflorescences. The inflorescence in our photographs, which also shows fruits, is obviously of female flowers, while the inflorescence in the Mozambican herbarium specimen showed the male inflorescence. Not only did we now have a name for our plant but we actually had a new species to add to our Zimbabwe Flora website. How could this be?

The specimens date from 1973 and 1981. These are relatively recent times in botanical terms, which explains the absence of Zimbabwe in the distribution mentioned in the old Flora Zambesiaca volume. This was published in 1963, when Zimbabwe was still called Southern Rhodesia. However, it now appears that the specimens were inexplicably missed by Anthony Mapaura and Jonathan Timberlake, who published the SABONET Checklist of Zimbabwean Plants, as well as by Mark and me for the Zimbabwe Flora website. One of the specimens was found by Tom Muller and who else could be better suited to prove you wrong or to teach you something new about the forests of Zimbabwe.

[Information about Pyrenacantha kirkii, including the images taken by Bart in Mozambique, may be found on the species page]