Expedition no. 15: Tree Society visit to the Vumba: 11 Aug 1999-15 Aug 1999

The following account has been taken from Tree Life no. 236 (October 1999) supplemented by some further notes made by Mark Hyde.

Wednesday 11 August 1999

Eight members (Andy MacNaughtan, Maureen Silva-Jones, Rose Greig, Werner Fibeck, Mark, Linda and Andrew Hyde (Robert had departed for Egypt the previous day) and Dick Harwin) of the Society combined Heroes' Days with the following weekend and visited the Vumba.

We travelled up to the Vumba from Harare and in the evening walked a few tens of metres into a patch of forest dominated by enormous Prunus cerasoides trees - a very successful invader.

There were also lots of nice Vumba forest things in the understorey and in a clearing some interesting compoitae and a large Triumfetta.

Thursday 12 August 1999

We stayed in a house called Shumba Rock, which is situated a few kilometres down the Essex Rd and is managed by the Vermeulens from Culemborg where we stayed in 1989. The house is raised somewhat giving a view over a valley and to the NW the Lion Rock range from the side. Apart from the bitter cold at night we were all very comfortable. My younger son was especially delighted to find a working video machine and a supply of tapes. As always the three days in the Vumba produced much interesting information which was new to me.

The first day, Thursday, was a local day. It was distinctly chilly and most people started the day in woolly jumpers, only to cast these off later in the more sheltered forest. The party split in two with the more intrepid group (Andy, Werner and Linda) going up towards the Lion Rock range and the other (Maureen, Rose and me) walking more gently down to the Essex Rd and from there exploring the Freshwater Rd.

Shumba Rock was formerly known as Cherry Trees and one of the main features of the forest surrounding the house was numerous large specimens of Prunus cerasoides, the Himalayan flowering cherry. I had no idea that this was so well naturalised in the Vumba forests; it does of course grow well along watercourses around Harare. It has striking bark with horizontal stripes, and shiny pieces of bark peeling off, so that the trunk appears shaggy. On the petiole are glands and the leaves do not smell of almonds when crushed as the native Prunus africana does. In the flowering season which I gather is short-lived, it has pink flowers.

The forest was notable for the False fig, Trilepisium madagascariense. How often we have been confused by this species in the past, but the milky latex, the very dark green leaves and the characteristic short acuminate apex serve to identify it. In the understorey were specimens of Dracaena fragrans. This plant is usually unbranched with very dark green leaves arranged around the central stem. Another Vumba species with milky latex we saw was Sapium ellipticum. This belongs to the Euphorbiaceae and has noticeably serrate leaf margins.

A number of alien species had successfully invaded the forest. One was a tall ginger with broad alternate leaves; at the apex of each stem was a large spike, now fruiting with orange fruits. I used to think that these were a species of Aframomum (a native genus in the Zingiberaceae, a species of which we were to see the next day at Ardroy) but Aframomum spp. have inflorescences which arise laterally from the base of the plant or the rhizomes. Matching this in the herbarium, it was a good match with Hedychium gardnerianum. This is a successful escape from gardens in other moist warm parts of Africa (e.g. S Africa and Mauritius). If this identification is correct, the plant will have yellow flowers with reddish exserted stamens. Perhaps any readers who live in the Vumba would like to watch out for this. The same plants were seen two years ago in the Cloudlands area of the Vumba.

As well as this exotic, the forest also had a large, possibly planted Loquat (Eriobotrya japonica), some specimens of Cestrum aurantiacum and lemon (Citrus limon) trees.

Another enormously successful invader is the Silverleaf (Desmodium uncinatum). We are very used to seeing this around Harare, but it was frequent in the Vumba too.

Several times we were confused by a rather anonymous-looking tree with alternate simple leaves; however the slightly grey underside gave it away – it was an Avocado Pear (Persea americana).

A remarkable woody climber we saw frequently throughout our visit was Strychnos lucens. Its typical Strychnos-like leaves are 3-veined from the base, very dark green and glossy and the plant bears striking paired tendrils. Another glossy climber was a species of Landolphia which was very common in the trees. The leaves are milky, a characteristic of the family (Apocynaceae) and the fruits spherical, about the size of a very large golf ball.

Also frequent in the forest was the climbing Canary Creeper (Senecio tamoides) with its yellow bunches of flowers. Another climber seen was Behnia reticulata. It is a monocotyledon with broad leaves and interconnecting lateral veins between the main veins. In this forest, it was in fruit with spherical white fruits 2 cm in diameter.

On the roadside banks of the Essex Rd a yellow-flowered composite, Hypochaeris radicata, was common, its stems arising from a rosette of basal leaves. It is one of the tribe Lactuceae with milky latex. This is a European species which is now well naturalised in the E Highlands and occurs typically on roadsides.

Down the Freshwater Rd, the road crosses a stream and there we came across a small tree with alternate simple leaves. This was Casearia battiscombei. When held up to the light the leaf lamina may be seen to have translucent streaks. The species belongs to the Flacourtiaceae. Nearby were the beautiful purple flowers of the Pride of Manicaland, Polygala virgata.

Further on, a remarkable find was a small shrub in the forest understorey 'with prickly leaves in whorls of four. This was an escaped Macadamia. We also saw it growing as a planted plant.

Other spp. seen were typical of the Vumba:

Aphloia theiformis, Bridelia micrantha, Carissa bispinosa subsp. zambesiensis, Choristylis rhamnoides, Cussonia spicata, Erythroxylum emarginatum, Halleria lucida, Keetia gueinzii, Podocarpus latifolius, Polyscias fulva, Rauvolfia caffra, Teclea nobilis, Toddalia asiatica with its fruits like tiny naartjies, Trimeria grandifolia and Vangueria apiculata.

In the afternoon, we drove up through an orchard to a further piece of forest. This was not so full of cherries and other exotics and we saw some additional species we hadn't seen earlier: Myrianthus holstii (the leaves of which Coates Palgrave says fall with an audible plop), the Soccer ball tree, Tabernaemontana stapfiana and Piper capense with its swollen joints. A small slightly fleshy herb on the forest floor might be Leidesia procumbens, a herbaceous Euphorbiaceae, but this needs to be checked.

All in all, a very successful first full day in the Vumba.

Mark Hyde

"Takkie's Forest" – Friday 13 August

Regrettably, Takkie Bannerman was away but instructions were left so that the magnificent chunk of Vumba forest was ours to explore. It must be marvellous to have this a stone's throw from the front door.

One of the hazards of Tree trips over weekends is that the second evening tends to be a bit more festive and the after effects cause cloudy vision the next morning. So here we were on the edge of the forest with an exotic worth mentioning with 3 veined leaves being glossy green, opposite and decussate. Simple – says my muddled brain it’s a Strychnos! Some discreet comments followed and Mark kindly pointed it out as a Cinnamon tree – Cinnamomum verum, the crush and sniff test of the leaves confirmed an aromatic odour. This large tree with a substantial bole must be quite old (perhaps Takkie may know the age) and is certainly majestic.

The species noted as we wandered into the cool gloom of the forest were much the same as the previous day's sightings and included the climbing Strychnos lucens (correct this time) with magnificent tendrils and the nondescript Tarenna pavettoides. Being forest the need for thick corky bark is minimised so as a result almost all those worth mentioning have only a smooth grey bark, which is not a reliable identifier especially when the leaves are sky high.

Luckily the dominant trees forming the canopy are Polyscias fulva, which, if we remember Tom Muller's suggestion, to look for the particular (curious) branching pattern, Albizia gummifera almost leafless and the triangular shaped leaves of Macaranga capensis. The largest of all the trees are the magnificent Newtonia buchananii, these provid¬ing the preferred habit for many of the epiphytic orchid species which as Werner pointed out, survive the dry periods from the moisture provided by the early morning mist rising from rivers and streams.

Some other details worth noting: Carissa bispinosa – we've often mistaken it for the more common Carissa edulis but here the spine is much more delicate with the length of the forked spines being just 1-2 cm long. Surrounding the clearing in the forest clumps of Brillantaisia sp. with lilac flowers light up the almost uniform green understorey. Here, Takkie propagates Tree Ferns – some of these being Cyathea cooperi which appear to be reasonably quick growing as most of these magnificent plants were of a good size – it was so pleasant here with the sun filtering through I could have stayed all morning! Anyway enough dreaming and back to the trees with a typically Eastern Districts Fig – Ficus craterostoma – with well defined truncation of the leaves, Syzygium cordatum with a label denoting the vernacular name as 'Mukute'

Albizia adianthifolia noted as 'Mujerenje' and found by accident, a thicket of ~@*!%* Smilax anceps – fiendish in a forest as the hooks are small and inconspicuous and takes the place of Acacia ataxacantha in the Eastern Districts!

With encroaching agriculture the forest fringe is narrow blending into what is for us more easily recognised woodland with Cussonia spicata, Pittosporum viridiflorum and Garcinia buchananii. The GPS, belonging to the Hydes and also referred as TOY by the technophobes, provided a quick and easy altitude reading of 1165 meters once we were out of the tree cover.

Further along the Essex road and after a quick stop at the dairy to replenish supplies Mozambique was only a few tantalizing km away and closer to the ill defined border the road cuts through an area of decomposing granites and shallow soils which are friable with nasty signs of erosion appearing regularly. The woodland on this ridge is characterised by stunted Uapaca kirkiana – large leaves and little else whereas in the fiat areas around the streams, thickets of Guava and a number of Avocado pear (Lauraceae) mask a well worn path which is evidently a back route into Mozambique – we learnt later there is a police post nearby for this reason. Despite being a relatively low altitude of 990 m the area is also moist as evidenced by the numerous colonies of lichens and epiphytic orchids hanging in the main from the two species of Brachystegia, namely Brachystegia spiciformis and Brachystegia utilis, the latter is easily distinguished as it looks like Mufuti – Brachystegia boehmii with a greater number of leaflets but of smaller size.

Apart from the common species we see on the highveld this attractive area had a few surprises such as Zimbabwe creeper – Podranea brycei with a few remaining pink tubular flowers, the climber Clematis sp. festooned in the riverine strip and masking what seemed to be Sapium ellipticum and a new one for me being Uapaca sansibarica.

On the slow walk up to where the vehicle was parked we came across Werner leaning at a strange angle over his tripod and camera focused on a large nest in the fork of a long expired Msasa. This appeared to be inhabited by wasps and was left alone!

The rest of the party suffering from the inevitable arboreal overload walked some distance along the road leading into the Burma Valley and its plantations of banana's, banana's and more banana's! Stopping by a small stream Maureen pointed out an Erythrophleum suaveolens, unfortunately rather hacked about, probably the actions of the road crew and not those desiring its potent properties as it is an 'ordeal tree' in traditional medicine. This lush spot also had Raphia palms and more epiphytic orchids but as we walked along the stream it became noticeable that the banana plantations recently established were only about 5 meters from the stream bank. With these friable soils the high potential for erosion surely a few more meters of vegetated river bank wouldn't harm the bank balance?

Our thanks to Takkie for making arrangements and to the Hydes for providing transport.

Andy MacNaughtan

Saturday 14th August

This morning, we set off down the Essex Road. The first event of the day was an abortive drive down the Cascades Rd. The name had suggested a lovely vision of waterfalls and their attendant interesting plants but reality was a long dull drive through wattle and gum plantations until eventually we came out on the Essex Rd again. We therefore retraced our steps and parked nearly opposite the Cascades Rd turnoff.

This was quite interesting forest with more false fig and naturalised coffee plants in the under¬storey. A short walk down the Essex Rd gave us a climbing composite with yellowish flowers, Microglossa pyrifolia and in a stream the striking purple inflorescences of Brillantaisia ulugurica.

However, a little hidden path into the forest hugging a stream took us to what was in my view the most exciting discovery of the weekend, namely the Excelsior Falls. The path slowly climbs, the stream becomes steeper and the water "whiter" until finally you reach a little man-made pool above which tumble the Falls. We have visited the Vumba for many years and did not know of them – they seem to be a well-kept secret.

In this moist mossy shade amongst tall Acanthaceae we found Vernonia wollastonii, a climbing species, Thalictrum rhynchocarpum, the leaves of which look like the fern genus Adiantum and a small herb, the wild sanicle, Sanicula europaea. Finally we returned and stopped for lunch. Close by was another Casearia, clearly a more widespread species in the Vumba than we had thought.

The afternoon was spent walking down (and sometimes up) the Essex Rd until we reached "Myrianthus corner". The altitude is lowish, between 1100 and 1200 m and an interesting if rather dusty flora was in evidence. It was very warm, particularly by contrast with the nippy temperatures of Shumba Rock and some members of the party took the opportunity to doze off in the forest.

Most striking was the climber Gouania longispicata, which as the name suggests has long spikes of yellowish flowers. It is very common in the Vumba. There was also Thunbergia alata, (Black-eyed Susan); this is sometimes seen around Harare as a garden plant, it has the unusual feature of a winged petiole.

Xymalos monospora is another common Vumba species with its thickly textured leaves which vary in shape and extent of serration. This belongs to a little-known family the Monimiaceae. The Zimbabwe creeper, Podranea brycei, scrambled in the forest edges, mingling with the abundant Microglossa.

A very interesting three days in which a lot of the interest is to be found in the species we could not identify. For example, near "Myrianthus corner" was a tall, striking yellow Senecio, new to me and a prostrate Lobelia, which again I had never seen before.

Sunday 15th August

We packed up to leave. Just after breakfast, we were unexpectedly visited by Darrel Plowes and his wife. Darrel had brought several boxes of marvellous botanical books for us to look at, many of which would be very useful in one's botanical library!

The drive back was non-botanical apart from the lunch stop in a small copse a few hundred metres off the main road just on the Harare side of Headlands. Although it had been badly hacked about the area was surprisingly rich and included Acokanthera and Sericanthe andongensis.

Mark Hyde