TREELIFE

JUNE 2001

SUBS ($200) WERE DUE ON 1ST APRIL. PLEASE USE THE INVOICE ATTACHED TO THE APRIL TREE LIFE WHEN MAKING PAYMENT

MASHONALAND CALENDAR

Saturday 2 June
Botanic Garden Walk – meet in the car park of the Botanic Garden at 10.45 for 11 am. where we will meet Tom. and continue with the topics of great interest to us all – ‘Jesse and Kalahari sands ‘.

Sunday 17 June.  Rick and Sally Passaportis in Ruwa have a lovely treed property very suitable for this month’s outing and because of its proximity to Harare is sure to be popular.

Saturday 30 June Please note the change of date which is to allow folk to return home after witnessing the solar eclipse.
Mark’s next walk will be at the home of Dr Peter Iliff at 7, Ernie’s Lane, Monavale. To get there, start at the intersection of Quendon Rd and West Rd and head westwards along Quendon, towards the Italian Club. Before you reach the Italian Club, take the first road to the left which is Lyndhurst Rd (no sign unfortunately!). Proceed along Lyndhurst and you will come to a fork; take the right-hand fork onto Ernie’s Lane and proceed to No. 7 which is at the end of the road.

Saturday 7 July Botanic Garden Walk

VIEWING THE TOTAL ECLIPSE 21ST JUNE 2001.

Residents in Mashonaland and Harare are well placed to observe this ‘once in a lifetime’ phenomenon. Take out your maps and pencil in a line between Makuti ( at the turnoff to Kariba ) through Mvurwi to Mutoko. North of that line the eclipse will be total. South of that line the eclipse will be partial.

Fuel allowing, it seems a pity not to position oneself within the total eclipse zone. It will occur at about 3.00 pm on Thursday 21st June, 2001, and will last about 15 to 20 minutes leaving you free to enjoy the rest of your outing in some other way.

Having drawn your pencil line on the map, you will see that the rural districts in the total eclipse zone include the Zambesi ( Chirundu, Mana and Kanyemba ), the northern part of Mhangura, Guruve, northern Mvurwi, Centenary, Mutepatepa, Mount Darwin, and Umfurudzi north of Shamva, as well as Mutoko.

The nearest viewing points to Harare in the total eclipse zone will be north of Mvurwi, and Mutepatepa, both areas being approximately 100 km from Harare on good wide tar roads. Where exactly to set yourself up for viewing will depend on your particular interests.

If all you wish to do is to witness the gradual darkening and then the eclipse itself, then the side of the road, for example, will be fine. On the other hand, if you wish to observe the effects on animal behaviour, then you will have to be more selective.

The reaction of birds will be interesting as they are likely to adopt a dusk behaviour. Woodland birds may be difficult to observe but birds of a water habitat may be easier to watch. So I, personally, would like to be near a large water body known to be rich in birdlife.

For those who will remain in Harare there is to be a mini expo at the Mukuvisi Woodlands with expert information, but remember you will be in the partial eclipse zone.

On the other hand, if you have farming friends in any of the areas listed above, and better still if they have a sizeable dam, go and sponge on them for the day. Otherwise you might consider some of the following suggested locations.

On the east of the Mount Darwin road from Bindura is the large Umfurudzi Dam about 35 km from Bindura, itself about 88 km from Harare. But you may find too much company here from local people. Near the Mutepatepa Club about 45 km north of Bindura on the Mutepatepa road (turn right at the Dundry Junction), there are a couple of large farm dams on Cowley and Ashcott. On the Harare Mvurwi road immediately before the Mvurwi township there is the picturesque Pembi Dam. Remember, both Mvurwi and Mutepatepa have fine Clubs which may well fete the occasion themselves. My preferred spot is at a large farm dam located on the road from Mvurwi to Horseshoe through the Suoguru Gap in the Great Dyke. From Mvurwi take the Centenary road past the Club and turn left after 5km on to a narrow tar road through farms including Galloway, Stockbury and Muirend. This road changes to gravel and then crosses the spillway and embankment of a large dam on the left. The site is very open with a grand view of granite kopjies and the dam. Total distance about 30 km from Mvurwi which itself is about 100 km from Harare.

Having gone this far, with the morning in hand, you might wish to go on to see the Raffia Palms in the Palm Block. To get there continue over the dam wall, through Sulugulu Farm and join the Centenary – Horseshoe road at a ‘T’ junction about 5km from the Dam. Turn right, soon on narrow tar, for about 5km and turn left on a gravel road before you get to the Musengesi bridge. This gravel road serves the Palm block with the Great Dyke on your left. Follow it for 15 km or more until you see a sign on your left to the Raffia Palm Botanical Reserve which is on Mawari Estate and Kungwa farm. A farm track of 2 or 3 km leads up to the Reserve. The splendid Palm groves are situated on the side of the Dyke hills alongside a Dyke stream which is soggy in places. Walking is, however, easy. After your picnic lunch at the palms retrace your path to the dam to be there by 3.00 pm. After the spectacle you return to Harare

Doubtless there are other options. Bat lovers might wish to go to caves to see if the bats are fooled. Will it be a feast for Bat Hawks? Will owls take advantage of the dusk conditions? Will night apes and bush babies leave their retreats and have to scuttle back in again?

For Mutare and Eastern Districts residents, Inyanga is too far south to provide good viewing of the eclipse. They would have to travel northwards beyond Nyamaropa to gain a satisfactory view. They also have a more serious risk of guti weather which could spoil the day. But in the Mashonaland north areas the weather is likely to be fine on this date which happens to be the winter solstice for us so go out and enjoy the phenomenon.

BUT PLEASE REMEMBER, ON NO ACCOUNT SHOULD YOU ATTEMPT TO LOOK DIRECTLY AT THE SUN EXCEPT THROUGH PROTECTIVE FILTERS WHICH YOU CAN OBTAIN FROM THE MUKUVISI WOODLANDS SHOP OR USE NUMBER 14 WELDING GLASS.

-JHWilson

BEITBRIDGE: GEM FARM: 6-13 JANUARY 2001 THE BADLANDS OF BEITBRIDGE: A GEM OF DIVERSITY

Even the intense January heat was not enough to sap everyone’s enthusiasm. While children had the time of their lives exploring the river bed and playing in the shaded swimming pool, some ardent accompanying adults went off on botanical forays in the heat of the midday sun. It was hard to resist an area so fascinating and varied, with scenery reminiscent of the badlands of the Wild West.

Gem Farm, where we were based, lies on the western banks of the Umzingwane River, some 35 km northwest of Beitbridge. Chris Cunliffe, the owner and our host, first settled here in the early 1960s, camping out under enormous Acacia galpinii trees with his young family as he slowly cleared the bush for the house and fields. Now the farm supports irrigated crops such as citrus, cotton and winter wheat; there are no cattle, only a few wild ungulates and the occasional itinerant elephant. From this base we explored the diversity of habitats on the farm and further to the south, and had a fascinating day visit to Sentinel Ranch further up the Limpopo, surely one of the most fascinating and scenic properties in the country.

What makes the whole area so interesting from a biological viewpoint is the combination of aridity (by Zimbabwe standards) and underlying geology, particularly the long narrow outcrop of Karoo sandstones, siltstones and silicified limestones (Forest Sandstone and the Red Beds) running from Maramani communal land near Sentinel across to Mtetengwe communal land on the other side of the Umzingwane. These are the same geological formations that reappear at Tshiturapadsi and in Sengwe communal land south of Gonarezhou, as well as on the Malilangwe Conservancy (formerly Lone Star Ranch) near Chiredzi. Under dry conditions sandstone weathers into strange twisted, precipitous formations with mini-cliffs, gullies, small caves and expanses of almost bare rock. As with the Matopos, the pattern and the interest is at various scales; it depends on one’s perspective. One can appreciate the landscape in miniature while on hands and knees, then stand up to be struck by the reddish cliffs rising like battlements across a bare plain.

Sandstone with its weird and wonderful formations creates a multiplicity of habitats. The lack of rain ensures that it doesn’t all become covered in soil and trees, which happens over much of the rest of the country. Where sand is deposited, sometimes in a patch just a metre or so across, it can hold moisture for quite a period, and it is here that those species perennating by bulb, corm or large rootstock are found. For example, in a couple of deeper sand patches we found that oddity Harpagophytum procumbens, the grapple plant, with its Star Wars fruit. In this general habitat there is a preponderance of papilionoid legumes and species from the family Malvaceae, including the endemic Hibiscus gwandensis, otherwise only recorded from Marungudzi mountain, which we passed close to last year on our Easter trip.

The original sands forming the sandstones were laid down in an arid environment at the end of the Karoo Period some 200 million years ago, later capped with extensive outflows of basalt marking the beginning of the Jurassic Period. It is in the siltstones, the Mpandi Formation, that dinosaur remains have been found. We saw a half-excavated and intact specimen of Massospondylus at Sentinel when we visited. Soils derived from these Karoo sediments have very little clay – they mostly comprise sand and silt – and are generally calcium-rich. Such a combination, not common in Zimbabwe, results in an unusual flora, which has more in common with that of Botswana and the low altitude northwestern part of Northern Province in South Africa.

Adenia spinosa. Photo: Petra Ballings. Source: Flora of Zimbabwe

Examples include the unusual, obese Adenia spinosa, a Medusa’s head stem-succulent, the grass Sartidia angolensis(only known from the Kalahari sands much further north), Kedrostis limpopoensis (endemic to this part of the Limpopo) and Pavonia dentata. The tree flora is not particularly rich, unsurprising considering the aridity and shallow soils. As over much of the southern lowveld, mopane is ubiquitous, although rarely found on sandstone or siltstone. Acacias are common, and become larger, more numerous and more diverse as one moves on to alluvial soils flanking the rivers.

Over the few days we spent most of our time exploring the sandstone outcrops on Gem Farm, across the Umzingwane River on Bishopstone Estates (where we encountered a surprisingly high population of Adenia spinosa), and on a part of River Ranch where a small dam regularly attracts elephants and makes for a wonderful landscape. Mark and others collected many plant specimens which, together with collections from the same area by myself, Isaac Mapaure, Rob Cunliffe and others over the last couple of years, will form the basis of a preliminary checklist of the area from Tuli to Umzingwane.

Although the sandstone was the focus of our attention this visit, we also spent time investigating the river beds, riverine forest and some dolerite hills nearby. Given the aridity there is a surprisingly varied and rich flora – from a herbaceous perspective perhaps more than from a woody – and the last two good rainy seasons have brought this out.

Many thanks indeed to Chris Cunliffe for so patiently putting up with a sudden invasion of 14 people of all ages who spread themselves over his lawn and took over his house and kitchen, but despite this made us all so welcome. Truly a fascinating part of the country to which we must return again soon.

-JRTimberlake

Contradiction

This combined Harare and Bulawayo branch visit attracted 14 people. Eight were from Bulawayo (4 Timberlakes, Tessa Ball, Anthon Ellert, JP Félu and Yolande) and 6 from Harare (4 Hydes, Maureen Silva-Jones and John Bennett). This was a great opportunity to spend a week exploring this area with its unusual sandstone geology, its low rainfall and its low altitude (c.500-600 m).

Jonathan Timberlake has set the scene and I won’t add to it. We were following in the footsteps of Jonathan and Rob Cunliffe who visited the area in February 2000 and made a collection of plants, which included 3 species new to Zimbabwe. Rainfall then was exceptionally heavy, making it difficult to get around – so completely different to our visit.

SATURDAY 6 JANUARY
In which we journey south to a dry land

The Harare folk traveled down in convoy. Luckily, the national fuel situation was going through one of it periodic, plentiful periods. However, we weren’t taking any risks and we filled up at every available stop (Chivhu, Masvingo, Lundi, Bubi and Beitbridge). A botanical stop was made at the Mtao Forest. Robert, Andrew and Linda decided to try out the GPS route mapping system by going in to the Forest while the rest of the party botanised along the edges. They were pleased to report that it still deserves the title forest. The plants were surprisingly interesting with some puzzling species found and almost deserves a little write-up in its own right!

A lunch stop was made by the Makwi River, just S of the Runde River, where we had stopped once before. Again, this is an interesting spot and whetted our appetite for the lowveld. From Beitbridge we drove northwards along the Bulawayo Rd and turned off towards Gem Fm, across the Bertie Knott Bridge.

The area generally was very dry; I thought incredibly so for January, but obviously expectations are low in this area. The roads were reasonable, although there was the odd scrape on the underside of our saloon car. Gem Farm, Plot No 5, sits high on the bank of the broad Umzingwane River in the magnificent, lowveld, riverine vegetation.

SUNDAY, 7 JANUARY  In which Mark and Anthon find the wrong kind of bees

The first full day began in the riverine vegetation just by the farm house. Here was a number of species which tend to be frequent in lowveld, and particularly riverine vegetation, such as Berchemia discolor (Bird plum), Cordia monoica (Sandpaper cordia), Philenoptera violacea(Rain tree) and Xanthocercis zambesiaca (Nyala berry).

Gymnosporia senegalensis. Photo: Mark Hyde. Source: Flora of Zimbabwe

Just behind the house was a puzzling Gymnosporia; it was a spiny shrub with broad leaves which were not in fascicles. Generally, it was quite like Gymnosporia senegalensis, but it completely lacked the glaucous leaves with a pinkish petiole so typical of the plant around Harare. Possibly it was just a form of this but the whole impression was of something different. Also on the alluvium was another puzzle – a rhus with spine-tipped branchlets. This turned out be Rhus gueinzii (Spiny rhus), a rare species of low altitudes in both the northern and southern divisions.

Everywhere the ground was carpeted with Tribulus zeyheri. This is similar to the fairly common, lowveld Tribulus terrestris (Calthrop) but has much larger yellow flowers and is altogether a much more striking plant. The fruits are similarly spiny though.

Also present was the three-thorned acacia, Acacia senegal, in this case the var. leiorachis. Many people believe that the two varieties, this one and var. rostrata are absolutely distinct entities worthy of being species in their own right. Var. leiorachis is usually a tree and its pods do not have a distinct beak at the apex, whereas rostrata tends to be a multi-stemmed shrub and its pods do have the beak.

A bit more walking brought us to the low, sandstone hills with their special flora. These astonishing-looking “badlands” contain a striking and remarkable flora.

Two exciting species found by Jonathan and Rob in 2000 are both from the Malvaceae. The first is Pavonia dentata, a sub-shrub with quite large, white flowers each surrounded by remarkable, linear, long-hairy, epicalyx segments. This is known from the north of South Africa but had never before been recorded from Zimbabwe. Also present was Hibiscus gwandensis. This species, endemic to Zimbabwe, was collected from Marungudzi, “on rim of ancient volcano” by Bob Drummond in 1958. This site appears to be the second record for this species.

A tree species new to me was Boscia foetida (the smelly boscia). At Gem, this was a small tree, with very dark green, small leaves, these arranged tightly around the branches forming a green cylindrical shape. It grew in crevices in the rocks. Near to a small dam, we came across a puzzling shrub; however, once we had spotted that it had compound leaves with 2 leaflets each, we realised that it must be a Balanites. However, this was not one of the two we usually see but the rare Balanites pedicellaris (Lesser torchwood). This differs from Balanites maughamii in having simple, not forked, spines and from Balanites aegyptiaca in its shorter petioles and smaller leaves. This is a rare Zimbabwean species, confined to the extreme south.

Commiphora pyracanthoides. Photo: Bart Wursten. Source: Flora of Zimbabwe

On the rocks near to the small dam was Commiphora pyracanthoides. This was not merely Commiphora glandulosa, which is a reasonably common species we see fairly often, but the low-growing taxon confined in Zimbabwe to the extreme south. At one point (e.g. in FZ) these two were subspecies of Commiphora pyracanthoides, but they now appear to be treated as separate species.

Another species new to me was a fairly frequent, low-growing Euclea, which was obviously different to any I knew. This turned out to be Euclea natalensis, but not the usual subspecies we see around Harare which is subsp. acutifolia; this one has narrower leaves and has been named subsp. angustifolia. This is a low altitude subsp. occurring rarely in Zimbabwe and also in S Africa and Botswana. Also on the rocks was Grewia tenax (the Small-leaved white cross-berry). This is a distinctive shrub, which, as the English name correctly implies has very small leaves which are almost circular, white flowers and also a 4-lobed fruit.

Apart from the specials, there were also a host of more familiar species. For example, the rock climber, Ficus abutilifolia (the Large-leaved rock fig) with its large, almost circular leaves. Acacia nigrescens, the knob thorn, was there, frequently catching at our skin and clothing. Grewia villosa, a shrub with hairy, almost circular, leaves was also common.

By the middle of the morning, Anthon and I, who were so engrossed in plants, had become separated from the main party, who had climbed to the top of the rocky ridge to enjoy the breeze. As we ascended the ridge to join them, I was suddenly aware of several angry bees buzzing around my ears under my hat. At this point, Anthon and I both shouted “BEES!”, turned and ran. Luckily the bees soon gave up, after stinging us a few times. How the others had made it past the nest I don’t know!

We then crossed the ridge at a different point and found, on the other side, a somewhat different flora. An exciting shrubby Acanthaceae with white flowers, was Petalidium aromaticum. Also present was the very attractive blue-flowered Blepharis diverspina with its very long, prominent spines. Indeed, the area was rich in Acanthaceae, with the yellow-flowered Justicia odora, another white-flowered species, Neuracanthus africanus, a white-flowered Justicia, not yet identified and Megalochlamys revoluta with blue flowers.

On our way back across the sandstone, a peculiar leafless shrub caught our attention. To our great excitement, it turned out to be Cadaba aphylla (Leafless cadaba). Although this is rare in Zimbabwe, the map in Coates Palgrave implies it is very widespread in the more desert-like areas of South Africa and Namibia. Strictly speaking, our plant was not absolutely leafless, there were some tiny leaves on new growth. The branches were greyish and fairly stiff with sharp points. No flowers or fruits were seen.

We came back to the homestead for lunch. Even at the start of the visit, the temperatures were very high and as the days went by it became hotter and hotter and a natural development was to begin the day before sun-up and sleep and/or swim in the afternoons. The swimming pool was a great boon – the water temperature was not cold but it was a few degrees below the air temperature and there was a tendency to lie in the water sticking out one’s nose like a hippo.

The first afternoon, with still reasonable temperatures, a small hardy group (Linda, Anthon and I) went for a walk back on to the sandstone, this time approaching the ridge from the other side. A steady flow of new, mainly herbaceous, records resulted, and also a very spiny shrub, which was a species of Lycium. The other variety of Acacia senegal, namely var. rostrata, was also seen, and in some riverine vegetation some enormous specimens of climbing Acacia schweinfurthii (the River climbing acacia).

MARK AND LINDA HYDE

MONDAY, 8 JANUARY  In which we don’t find a heffalump or a woozle

This was the second day of our visit and turned out to be very interesting. Our whole party travelled a few kilometres back down the road towards Beit Bridge on the road we had originally come in on. We were going to the Elephant Pool/Dam, which turned out to be aptly named with elephant tracks and dung in abundance. Jonathan warned us to be on the look out for elephants and to treat them with caution since elephants in the area had been shot at and could be dangerous. Adjacent to the dam were several large outcrops of sandstone which yielded some interesting plants like Spirostachys africana, Sterculia rogersii, Tricalysia junodii, Tarchonanthus camphoratus, Rhus gueinsii, Olax dissitiflora, Euclea natalensis (a subspecies of which we do not see often) and Grewia villosa. In an area where the sandstone had weathered to produce pockets of sand we found Harpagohhytum procumbens (the devils claw) which gripped tightly onto the shoes of many of our party. We were lucky to see this plant in flower (it has pink, white and yellow flowers which have the typical shape of the Pedaliaceae family. Another interesting plant that Jonathan showed us was a small bulbous plant with a pinky brown bulb, Schizobasis intricata. A species of Vitex was found which had us all puzzled. No wonder as we discovered later that Bob Drummond had been shown a specimen from this area and he could not put a name to it except Vitex sp.

• Having explored one part of the Sandstone outcropping some of us crossed over the river course below the dam wall towards another part of the sandstone. On the way we came across Acacia senegal var leiorhachis and A. senegal var rostrata.I was wondering why Rhigozum obvovatum was not on our Zimbabwe tree card when it is included in Coates Palgrave and I remember having seen tree size plants before. Quite fortuitously we came across a specimen of R. obovatum which was definitely tree size. A bit further on Yolanda Felu noticed a horned adder curled up beside the path we were taking, almost perfectly camouflaged on the sandstone rock. This discovery led to great excitement for everybody with J.P. and Jonathan taking pictures. The snake perhaps could have done with less attention! I was lucky enough to come across an Olax dissitiflora with a few fruits, never having seen this tree with ripe fruits before. The geology on this sandstone area was interesting in that in some places the rock seemed to be composed of rounded clumps of stone which could almost have been placed by hand. In a few places at the end of an outcrop there were untidy piles of stones where they had come away from the main mass of rock.

We saw more of the pretty little endemic Hibiscus gwandensis with its pinky-red-orange flowers and J P and I found another plant of the curious Cadaba aphylla which somewhat resembles asarcostemma or Euphorbia tirucalli but is bluey green and for most of the year has no leaves. From a distance the stems appear to be stiff and spiny but are actually fairly soft.

On the way back to the cars we came across a small grove of Tinnea rhodesiana bushes with their curious mauve and yellow flowers and distinctively shaped inflated fruits which bear a slight resemblance to the Cape gooseberry. On returning to the dam we found the Hydes and one or two others resting under a shady tree. Mark had been busy collecting a fair number of grasses and herbs of interest.

We returned to Gem farm for lunch and a rest. Later in the afternoon a few of us set off for the Cawood property on the other side of the Umzingwane River opposite Gem Farm. J.P. had noticed some Euphorbia cooperi on the other side of the river on a sandstone hill the previous day. The sandstone hill was almost completely bare at the top with only a few trees and a large number of Aloe chabaudii. There were patches or areas of denser vegetation around the edges of the hill and we were able to add the following to the list of Cear the river. Up on the sandstone we saw Jatropha messinica, Peltophorum africanum, Commiphora pyracanthoides, Euphorbia   cooperiandXanthocercis zambesiaca and last but definitely not least Sesamothamnus lugardii, and Adenia spinosa the big plants of which seem to squat on the rock like green skinned buddhas. It was very good to see that both of these last two had small seedlings growing nearby. There were several Adenia spinosa in fruit aplenty so I was able to collect some ripe ones

-ANTHON ELLERT.

TUESDAY, 9 JANUARY  In which we follow in the footsteps of the elephant’s child and meet a dinosaur

We headed across country to the famous Sentinel Ranch, which, after Nottingham Ranch, abuts the Limpopo to the west of Beitbridge. Our first stop was in fact on Nottingham, where Jonathan showed us Acacia stuhlmannii. This is a very rare acacia in Zimbabwe, only occurring at a few places in the extreme south. It is a multi-stemmed shrub, it has straight thorns and (these are the two important features) shaggy-hairy branchlets and woolly pods. A few hundred metres on, something unusual caught my eye and two interesting weedy Chenopodiaceae were collected. One was the spiny Salsola kali (another species recently discovered new to Zimbabwe by Jonathan) and the foetid Chenopodium hederiforme.

Passing “the sentinel”, which is a tall, watchtower rock from which the ranch takes its name, we eventually arrived at Sentinel Ranch, where we reported in. The first thing we did was non-botanical but most exciting and unexpected. We were taken a few kms away from the Limpopo river into the sandstone hills to see the site of a dinosaur skeleton. This skeleton is of a species of Massospondylus, which was found by Digby Bristow’s mother some years ago, on a bare rocky slope. The skeleton has been partially excavated and is loosely covered by roofing which can be removed. The creature itself died in a funny twisted position and it was not easy to see which bit was which.

The woody flora at the dinosaur site consisted of three commiphoras: Commiphora glandulosa(i.e. not pyracanthoides this time), Commiphora viminea (the zebra-bark commiphora) and Commiphora tenuipetiolata (the latter is a very local one confined in Zimbabwe to the south). Also present were Kirkia acuminata, Euphorbia cooperi, Pappea capensis and Ficus cordata subsp. salicifolia. Some very fine examples of Sesamothamnus lugardii (Sesame bush) were also nearby.

We then walked up to the top of the hills where there was a natural plateau which had been dissected. Disappointingly, the whole area had had too little rainfall and, to my amazement, even in early January there was almost no green herbaceous ground flora. We will clearly have to return to this fascinating area.

We then moved on to a rich herbaceous flora on the alluvial soils in the Limpopo valley through a dense stand of a purple-flowered composite, whose aroma was released by the vehicles crushing the plants. At the time, I erroneously believed this was a Sphaeranthus, but it was later identified by Bob Drummond as Litogyne gariepina. Thanks to Bob for correcting me there – not the first time I’ve made that error.

A short walk before lunch took us though Acacia xanthophloea (fever trees) in their classic Kipling site, Ficus sycomorus, Hyphaene and more Berchemia discolor. A very common introduction on the riverine sand was Nicotiana glauca (Tree tobacco). This is a large, hairless, grey-leaved tobacco with yellow tubular flowers, introduced from S America and typically colonising lowveld rivers. Another species in the same habitat is a yellow-flowered composite, an alien from SW USA and Mexico, called Verbesina encelioides.

Lunch under a large riverine tree was followed by a short excursion to the fast-flowing Limpopo and a quick dip by some to cool off. Fortunately, “yonder plated man of war by which I mean, O Dearly Beloved, the crocodile” did not choose Tree Society child for dinner.

For the final stop of the day, we drove up into the hills following a dry river bed. We left the cars in the shade of some trees and continued on foot. Here we repeated many of the riverine trees seen earlier. A new subshrubby species was Barleria albostellata, a very common species in the Matopos, which grew in a rocky location.

Perhaps the most extraordinary thing was a large, showy, perennial, purple-flowered Cleome. This was later identified as Cleome oxyphylla var. robusta. The river made its way through a steep-sided gorge which was the ideal dam site. The resulting body of water again proved too tempting for the parched and weary enthusiasts, who indulged in a second swim.

As we drove back through Nottingham, several plants of the exotic Calotropis procera caught our eye and one was collected and pressed. This is probably a new record for the southern division.

All in all, an exciting day, which showed the enormous interest and potential of Sentinel. However, it is clear we need to return after the area has had some rain.

The climax of the day was a total eclipse of the moon. Conditions for seeing this were excellent and even at totality the moon’s face was still clearly visible in a reddish-brown light.

WEDNESDAY, 10 JANUARY  In which we travel up river and visit the local inhabitants �

By now, the heat had built up and a maximum of nearly 40C was achieved. We had a local day and walked north alongside the Umzingwane River, mostly through shady riverine vegetation but occasionally though citrus plantations, until we reached the Smith’s lovely home.

Trees seen included Acacia grandicornuta (horned thorn) and Acacia mellifera (hook-thorn). A new climbing asclepiad turned out to be Secamone parvifolia. It was also a good day for new weed species – e.g. the grass Cenchrus ciliaris (foxtail grass) and Boerhavia erecta.

At the Smiths’, under a spreading and shady Combretum imberbe (leadwood) we were plied with drinks and food and in return for the splendid hospitality identified some of the nearby riverine trees.

We then walked on, this time alongside very open fields in the exceedingly high temperatures until we reached the Trethowans’ home. There, after a very welcome swim in the pool, we had a light lunch and then Brian ferried us back to Chris Cunliffe’s home.

After a siesta, in which we looked at the specimens collected in February 2000, Anthon and I went back on to the sandstone hills. It was extremely hot, but cooled off as the sun sank lower.

Linda chose to walk back in the river bed and noted three points of interest. Firstly, that the Faidherbia albida plants were of three different sizes:

• • 10-20 cm high, presumably having been washed down to the river sands and germinating in the last 2-3 months;
  • 1-1.5 m high, possibly from last year’s floods and having a root system enabling them to tap the still high water levels under the sand;
  • mature trees, probably more than 20 years old.

The second point was that in the river bed most thriving seedlings were associated with cowpats and lastly a large variety of weedy plants had germinated in the river bed.

THURSDAY, 11 JANUARY  In which we go down to the river for weeds and up to the hills for a change

With the heat now building up to excessive levels, we were up very early indeed for a walk. In fact, conditions for walking had really become uncomfortable by 9 a.m. Linda and I decided to follow up on her walk of the previous day and to go down onto the sandy bed of the Umzingwane River to collect everything and list them properly. What is surprising is that many species seen were rare weeds, confined either to this part of Zimbabwe or low altitude rivers.

A full list and discussion would probably be out of place in a Tree Society newsletter. However, one or two species might be mentioned. Quite frequent was a composite which was new to me; this was Doellia cafra (formerly Blumea cafra).

A small white-flowered herb seen was Samolus valerandi. This species also grows in the UK and I remember seeing it once in a stream in Suffolk, but it was always rare. In Zimbabwe, it also seems to be very rare. Also on the sand was Lactuca serriola, an exotic seen quite frequently in Bulawayo and Harare; this is probably a major extension of its range.

This work needs to be followed up at a different time of the year and in a different season.

This day, the midday siesta was more or less essential. The maximum temperature recorded was 41C.

In the late afternoon, Anthon, John and I drove to a prominent, dolerite hill nearby, on the top of which is a radio repeater mast. I was reminded of the expression “mad dogs and Englishmen “, but we took the climb slowly and because of that and the fact that the sun was disappearing behind a large storm cloud, meant that conditions were fairly tolerable. This was a significantly different flora with a number of new species. At the summit, we saw Adansonia digitata (Baobab), Commiphora marlothii (Paperbark), Cordia monoica (sandpaper cordia), Ficus tettensis (Small-leaved rock fig), Gardenia resiniflua (Gummy gardenia) and Steganotaenia araliacea (Popgun tree). A number of interesting legumes were found and these await naming.

In the evening, back at Gem Farm, a ferocious storm broke with gusting wind, vicious lightning and thunder. However, Chris said he thought little would come of it and indeed it was “full of sound and fury, signifying nothing”. Apart from literally a few spots of rain, nothing happened.

FRIDAY 12 JANUARY In which we all do our own thing

After the break in the weather yesterday, the day was definitely a lot cooler. Linda and I took a local walk which included the irrigated cotton fields, the citrus plantations and the sandstone hills again. Most of the plants were repeats from earlier days. At the edge of the irrigated cotton we found two plants of interest. One was Holubia saccata. This is a small semi-succulent herb with yellow flowers and fruits which are winged like combretums. This is a local species occurring in the S and E of Zimbabwe. From the same family, Pedaliaceae (the sesame family), we found Sesamum triphyllum.

SATURDAY 13 JANUARY
In which we say farewell to an enchanted place we hope to return to

We packed up and drove across the Umzingwane on a causeway and from there back to the main Bulawayo/ Beitbridge road. This is a much shorter and more direct route than our way in.

As we returned, we reflected on a wonderful week. Our very great thanks go to Chris Cunliffe for welcoming such a mass invasion and to Jonathan for making the arrangements.

MARK AND LINDA HYDE

MARK HYDE  CHAIRMAN