Baikieas, Baphias and Bauhinias The Zimbabwe flora team goes to Hwange - part 1

By Petra Ballings and Bart Wursten

The Zimbabwe flora team would like to acknowledge with thanks a generous donation by John McLoughlin towards the cost of this expedition.

Monday, January 4 2010

Getting up rather early to go look at plants is not everyone's idea of a sane way to pass the time. After all, plants, unlike birds or wildlife do not tend to fly off or disappear during the heat of the day. However, the aim of our trip is to reach Main camp in Hwange National Park and that is at least a 10 hour drive from Harare in our more than middle-aged Landcruiser so the Zimbabwe flora team gets going at the crack of dawn.

Two years ago, during our trip to Tuli (see Tree Life April 2008 or this web page), we managed to survive serious car trouble, torrential rains and the total chaos that Zimbabwe was in at the time and we feel confident that this trip will be a piece of cake in comparison.

We resist all temptations of interesting plants and flowering trees, beckoning us along the way and manage to reach Bulawayo only slightly behind schedule. Despite the improved circumstances in the country, compared to 2 years ago, it still takes us 3 fuel stations to find diesel. Thoughts like 'Oh no, not again!' quickly come to mind but we do manage to fill up in the end. Somehow it always seems easier to get into Bulawayo than get out again and it takes a couple of wrong turns before we find the right direction.

However, we do arrive at Hwange Main Camp in good time, pay our dues and find our booked cottage ready for us. We also find that we are probably the only visitors in the area. Apart from the staff, the camp appears completely deserted and we may well find we have more than 14.500 square kms (about half the size of Belgium) of undisturbed wilderness to ourselves.

A quick tour of the grounds mainly gives us a series of cosmopolitan weeds, such as Gomphrena celosioides, Alternanthera pungens and Guillemimea densa. All are well adapted to any place seriously disturbed by man. Where other plants disappear because they get trampled by too many feet, these species actually thrive. With hooked seeds and sticky burs they clamp themselves onto fur, skin, socks and trousers and spread themselves wherever we go. The next days will show well what perfect agents of dispersal humans are. At every camp, picnic site or viewing platform, wherever people are allowed to leave their vehicles, the same series of weeds have taken over in an otherwise diverse and almost pristine wilderness.

It is not only weeds at the camp of course. Under the majestic thorny crowns of camelthorns (Acacia erioloba) with their broad, curved pods covered in grey velvety hairs, we find several small creeping plants. One is Tribulus terrestris, with its lovely yellow flowers and the rather ominous popular name "Devil's Eyelashes' referring to the small viciously spiny fruits. It uses a similar way to disperse its seeds as the weeds by sticking to the hooves of animals or pierce the soles of your boots.

Another find is Hermannia quartiniana with lovely bell-shaped flowers. It's a tiny herbaceous relative of the enormous African Star-chestnut or Tick-tree (Sterculia africana).

Electricity is as absent as other visitors so we tackle the "braai" for our cooking while it is still light. After dinner, in the glow of the campfire, we enjoy the sounds of the African bush: crickets, hyenas whooping and giggling nearby and even the distant roar of a lion in an otherwise silent and pitch black night. A perfect start to our trip.

Tuesday January 5 2010

On our first full day we want to find, record and, where possible photograph, as many species of typical Kalahari sand flora as we can so we decide to do the large loop to the Kennedy Pans. This very quickly turns out to be a rather over-ambitious plan. There is so much to see that we will never be able to do this in time and we decide to do the shorter Dopi Pan loop instead.

It is a perfect display of the flora we want. Densely wooded areas, interspersed with open grasslands and seasonal pans. At drier times these pans attract both the wildlife and the people who come to watch them but now they are devoid of both. At this time of the year animals are able to find food and water everywhere and have no need to stay close to these more permanent waterholes.

The woodlands are dominated by large trees of Zambezi Teak (Baikiea plurijuga) and an understorey abundant with Sand Camwood (Baphia massaiensis) and the Kalahari bauhinia ( Bauhinia petersiana var. macrantha). All are in flower and sparkle the landscape with small and large white flowers.

Large False Mopanes (Guibourtia coleosperma) are also flowering but are more conspicuous because of the distinct orange-yellow bark with large black patches, giving the trees their freshly burnt appearance.

Having only been to Hwange during the dry season, it is amazing how lush, green and different it is now. Masses of flowering herbaceous plant species colour the roadsides. Many are typical for this environment and we are seeing most of them for the first time in the wild.

Acanthosicyos naudinianus is a creeping species of wild cucumber. Since it usually has nothing to climb into in the almost bare sandy patches it inhabits, it has no use for tendrils, which are modified into spines.

Dicerocaryum eriocarpum is a close relative of the more widespread Devil thorn or "Boot-protectors" (D. senecioides). It looks very similar but has broader, unlobed leaves and the typical double-spined woody fruits are more rounded and hairy.

Another relative takes its dispersal mechanisms to even further extremes. Harpagophytum zeyheri, aptly named the Grapple Plant, has large flattened woody fruits armed on the margins with several rows of curved extremities bearing recurved spines. Even the largest mammals, buffalo, giraffes or elephants, can not avoid getting hooked by these fruits and help disperse them. The plants we see show spectacular trumpet-shaped flowers, at least 6 cm in diameter, deep pink with yellow throats.

Even one of the more familiar sights in Zimbabwe manages to look somewhat different. The Flamelilies (Gloriosa superba) of Hwange are the brightest of orange you can imagine. You can see them from far away when the strings of flowers climb into the otherwise green vegetation. Common as they are in Zimbabwe, one tends to forget how extravagantly shaped and stunningly beautiful these almost alien looking flowers really are.

In the afternoon, many dozens of new species later, we get back to camp and even managed to see some zebra and giraffes to remind us there's more to life than just plants. A fantastic storm soon turns the whole camp into a temporary marsh. There is nothing quite like rain in Africa. One moment it is a hot and sunny day, when suddenly the floodgates open up and in less than an hour more rain falls than London sees in several months. The thunder and lighting, the enormity of it all, the sudden downpour temporarily cooling everything for a short while. An area such as Hwange may receive only a handful of these torrential showers, all in a period of a few months, so many plants, in fact all life forms, need to be ready and make the most of these brief periods when everything is plentiful.

There is not much point in going out again. We go through the findings of the day, download pictures and wait for the rain to stop. When it does everything is soaking wet, including the firewood; and still no electricity. Many attempts, matches, newspaper and candles later we do manage to get enough of a fire going to cook some supper. The weather has obviously woken up every species of frog occurring in the region as their orchestra of calls form the soundtrack for this evening.

At 9:30 PM the electricity attempts an appearance lasting literally one single second. Recharging cameras, GPS's and computers will have to wait. Definitely time for bed.

Wednesday January 6 2010

While 2 of the team are still dreaming their dreams, Bart gets back into his former guiding mode and manages to get the fire going, earning points by waking up the others with a nice cup of tea. Today's plan is to visit similar habitats as yesterday but to venture outside the official boundaries of the National Park. This offers the relative advantages of legally being allowed to leave the vehicle and have a good look around and also collect some specimens of species that need closer inspection to identify. The main road outside the National Park offers perfect opportunities to do so.

Our first stop, at a railway crossing, immediately proves to be a treasure trove. The area has been partly cleared of trees and we find many of the herbaceous species we saw the day before as well as many new ones. As usual we are confronted by several species of Indigofera. With more than 80 species it is the largest genus in the country, ranging from tiny annuals to large woody shrubs. There is hardly a fieldtrip possible without finding at least a couple of species and it is always a daunting task to get them identified. There is no recent comprehensive literature on them and, while some are quite distinct, others are deceptively similar. Trawling through all the specimens of a genus at the National Herbarium may work fine for most genera but the numbers in Indigofera make it nearly impossible. Still, as always we record and photograph all possibly relevant details, collect a specimen and promise ourselves, as always, that one day we'll get all our Indigofera specimens together and go for it.

At the edge of the woodlands, we get a chance to take a good look at some of the woody species such as Acacia fleckii, a species similar to Acacia erubescens. It is most easily distinguished from the latter by the much shorter petiole, bearing a much more conspicuous saucer-shaped gland and longer leaves with more pairs of pinnae.

We found a nice comparison between the Lavender croton (Croton gratissimus) and its smaller cousin C. pseudopulchellus which were growing right next to each other. As both species were flowering, it was easy to see the difference between the long spikes of C. gratissimus and the short cluster of C. pseudopulchellus. Both species have very discolorous leaves, the undersides shiny silvery-white. The leaves of C. pseudopulchellus are considerably smaller and much more densely dotted with reddish-brown scales than its larger relative.

We slowly moved on, making several more stops to inspect the woodlands. Fire has played an important role in the ecology of this environment, even since before the influence of man. Many species have adapted to overcome the dangerous effects of fire. Most trees either have thick layers of corky bark to protect them or have several thin layers of peeling bark, which can be easily shed and replaced by new growth. Many species, even tiny annuals, produce hardened fruits and seeds, which are able to survive fires or even need fire to break their shells and germinate.

Many plants have evolved to largely growing underground, protected from fires, occasional frosts or seasonal flooding, only to send up annual shoots with flowers and fruits, whenever the time is right. These suffrutex species or underground trees have evolved in many different families of plants and are particularly numerous in areas of Kalahari sand. We encounter several of these interesting plants today. Some are well-known and widespread in Zimbabwe, such as the Marama Bean (Tylosema fassoglense) a yellow-flowered relative of the Bauhinias. From an enormous woody, tuberous rootstock, it grows masses of creeping stems each year, which flower profusely, bare fruit and die back again.

Other species we see for the very first time. Ancylanthos rubiginosus is a member of the Coffee family (Rubiaceae). It sends up several shoots every year bearing pretty orange-yellow flowers and fruits crowned with the golden-velvety remains of the calyx.

Dichapetalum rhodesicum is member of the Poison-leaf family (Dichapetalaceae), a small family with only a handful species in Zimbabwe. In both species the shoots are normally only about 60 cm tall but in some years, when fires floods and frosts are absent, they can grow somewhat taller.

As we get closer to the main road between Bulawayo and Victoria Falls, signs of human disturbance increase but the Kalahari sand vegetation still dominates. To our surprise we even find a small store seemingly in the middle of nowhere. It is proudly named the "Save-The-Nation Store". It certainly saves us. The shops at the camps in the National Park have long since closed, as have the Restaurants and bars. We're very happy to find some bread and other supplies to last us through the rest of our trip.

Right outside the shop we also find another interesting tree, the Manketti-tree (Schinziophyton rautanenii). A fascinating and unusual species in almost every aspect. It can be an impressively large tree with smooth pale golden-brown bark; it has very discolorous, palmately divided leaves, densely covered in stellate hairs; it has very conspicuous glands on the petiole where the leaflets are joined; it exudes copious clear sap; it has unisexual flowers with sexes on different trees and the female trees bear large velvety fruit with a single, very hard seed containing a bright yellow edible oil. If Meg Coates Palgrave says: "All trees have labels to advertise their names", than the Manketti-tree has billboard-signs to do so.

On our way back to camp, we stop at a small seasonal pan, obviously visited more by cattle than wildlife but still offers new interesting plants. Petra gets particularly excited when she discovers her speciality: a small fern. It is a species of Marsilea, an inconspicuous aquatic fern, one of the very few fern-like plants able to survive in this generally hot and dry, very fern-unfriendly environment.

In the late afternoon we drive to Nyamandhlovu platform. Often the busiest place in Hwange at sunset, today there are no other people and few animals. Lots of birds around the pan, four hippos splashing about; a curious black-backed jackal having a look and a herd of impala grazing in the distance. All very peaceful and quite enjoyable.

A quick survey of plants largely yields the same weeds becoming the standard. Back in camp there is still no power, nothing new there. Tomorrow we move towards Sinamatella. It promises to be botanically very different but do we dare to hope for improvement on the electricity front...?

Sinamatella Surprises The Zimbabwe flora team goes to Hwange - part 2

By Petra Ballings and Bart Wursten

Thursday, 7 January 2010

Getting up early during this fieldtrip is generally not a problem. The sun rises early and soon warms things up so a long, lazy morning in bed is pretty much out of the question anyway but so far, at first light, we've also had a somewhat annoying wake-up call by a bird ticking against our bedroom window. A confused Southern Masked Weaver is trying to sort out its virtual competition in the form of its own image. Sinamatella is quite a distance and no doubt we'll find a few plants on the way to slow us down. We expect to take pretty much all day for the trip so the early start is welcome.

The terrain opens up almost immediately. The dense Kalahari sand forests are replaced by an open mosaic of grassland, open savannah woodland and frequent pans. Just out of Main Camp we find one of the most photogenic and majestic specimens of Acacia erioloba. Its relative fame extends even to the back-cover of Jonathan Timberlake's Field Guide to the Acacias of Zimbabwe. Close by, a group of giraffe are almost dwarfed under the crown of a giant Leadwood (Combretum imberbe). The general soil composition is still dominated by Kalahari sand and we frequently pass through areas with denser scrub, including the well-known species from the previous days and other interesting species like the apparently simple-leaved Philenoptera nelsii and Terminalia brachystemma. We are briefly greeted by a little Steenbok, a small elegant antelope with definite 'bambi'-looks.

We regularly have opportunities to stop and have a closer look at the vegetation around the various viewing platforms, such as Nyamandlhovu, Guvalala, White hill Pan and Shumba Pan. The same, by now familiar assortment of man-dispersed weeds is recorded at every one of these places but it also gives us the chance to photograph and record interesting new species, such as Neorautanenia brachypus and Otoptera burchellii. Both are twining species in the bean family (Fabaceae-Papilionoideae) with attractive mauve to violet flowers and blue-green 3-foliolate leaves.

At the Shumba picnic site we can briefly hide from the fierce sun under an assortment of enormous, shady riverine trees, though there is no escaping the oppressive humid heat. Several impressive Jackal-berry trees (Diospyros mespiliformis), with their straight trunks and conspicuous almost blackened bark, grow from ancient termite mounds. Large Raintrees (Philenoptera violacea, formerly better known as Lonchocarpus capassa), trunks bent and the large, branches horizontally spreading, would form the ideal leopard's resting place. The centre piece at the site is a giant and ancient Common Wild Fig (Ficus burkei), which has completely enveloped and long since killed an old Jackal-berry.

Shortly after leaving Shumba, the scenery chances again. We are driving through large areas of mopane woodland before arriving at Masuma Dam, one of the larger viewing platforms in the National Park. It's a solid, thatch-covered structure, built on a small hill, overlooking a small dam. At this time of the year, like most pans we have seen, it is full of water and pretty much empty of wildlife. With ample supplies of food and water everywhere, there is little incentive to come to the more permanent watering holes like Masuma, which, during the dry season are often teeming with animals, desperate for a drink. Only a small pod of hippos have taken up residence in the dam. The lack of wildlife doesn't bother us.

The small, fenced in area by the viewing platform offers us a good opportunity to look at the vegetation. A Splendid Thorn (Acacia robusta subsp. clavigera) is full of its typical small white balls of flowers. Nearby two young Nyala trees (Xanthocercis zambesiaca) are in fruit. A member of the pea-family (Fabaceae-Papilionoideae), its small, fleshy, berry-like fruits are very unusual. Though the species certainly occurs naturally in riverine areas of the park, the small specimens here have most likely been planted in the hope that they will eventually give some shaded parking to visitors' cars.

In the mopane dominated scrub around it grows a species of Hibiscus, H. caesius. Like many of its relatives, it has large, showy, pale yellowish flowers with a very dark maroon-red heart. This one is recognized by the very long, almost spine-like epicalyx lobes. Nearby a portion of the ground is covered with small but beautiful, intensely blue-violet flowers, belonging to the Veld-Violet (Aptosimum lineare). A taller plant of Sesamum triphyllum with large, bright pink, almost square flowers, forms a striking contrast. The fences, supposedly protecting us from untamed and wild Africa - or is it perhaps the other way round? - are mostly overgrown with an array of climbers. There's Cocculus hirsutus with tiny green flowers and leaves so variable that the small mucronate tip is just about the only constant factor. Ctenolepis cerasiformis, a very small-fruited cucurbit, is more easily distinguished by it large, frilled stipule-like appendages. A Morning Glory, Ipomoea dichroa, with conspicuously white undersides of it 3-lobed leaves, is growing from the fence into a near-by Snow-berry shrub (Flueggea virosa). Covered in small white berries, it seems aptly named.

Just beyond the fence, the old carcass of a bulldozer remains only barely visible under its cover of tall grasses and more climbers, including Helinus integrifolius, Ampelocissus africanus and unrecognizable wild cucumbers. The most exciting find is unexpectedly provided by what must be the most abundantly common tree in these parts of southern Africa. Anyone who has ever been out in the bush has seen it, knows it and has driven though mind-numbing stretches of it but who would able to say what the flowers of mopane look like? It is certainly the first time we see them, at least consciously. They may not be beautiful or showy but small masterpieces of evolutionary adaptation they certainly are. Small reflexed sepals and no petals at all but very long, thread-like filaments bearing anthers the size of grains of rice dangle freely in the wind. It is a perfectly adapted construction to make mopane one of the few truly and exclusively wind pollinated trees.

After some lunch, entertained by unusually playful hippos, we move on. Near the turn-off to Robin's Camp, the terrain becomes more rocky with large boulders and even small koppies dominating the landscape. Different trees appear, preferring these rocky habitats, including the Tick-tree (Sterculia africana) with its smooth bark in a silvery-grey and purple-brown patchwork pattern. The Paperbark Corkwood (Commiphora marlothii), gnarled and twisted, seems to grow straight out of the rocks; large strips of the green papery bark hanging from the trunk, loose but still in the windless heat of the afternoon. A Bell-bean (Markhamia zanzibarica) still bears the last of its striking dark maroon spotted flowers. Some of the boulders are nearly covered in a cascading spray of large 5-lobed leaves, belonging to the grape-like vine Ampelocissus africana. The relatively bare ground surrounding the boulders, here and there sprouts large solitary heart-shaped leaves of Stylochaeton pubescens. The arum-like flowers of this species are only rarely seen. They develop mostly underground and bloom before the conspicuous leaves appear.

As we get closer to Sinamatella, the vegetation becomes more and more dominated by mopane. Often bare and open, these areas offer good opportunities to see wildlife at most times of the year but during the few rainy months the bush is thick and lush. It appears utterly empty of wildlife until suddenly a female lion crosses our path. The total surprise is entirely mutual and she quickly disappears into the bush. For us, getting out of the car to take close-up photographs, has been put in a somewhat different perspective.

We arrive in Sinamatella in the late afternoon and discover that the electricity is working! All batteries and computers are being recharged and we will have a cold drink at dinner. Ah electricity, one does not realise how dependant the modern world has become of it until it is not there ...

The whole camp seems completely deserted but still very functional and with one of the best views in the country, overlooking the seemingly endless wilderness like eagle in flight. In the evening we sit outside and enjoy the silence. Another dark sky with a trillion stars looking down on us.

Friday, 8 Jan 2010

After a more than excellent night sleep, without unsolicited wake-up calls, we set off to Mandavu dam. On the way, the different, more stony soils, are often bare but in the shade of bushes and trees many interesting new plants are found. Acanthaceae seem to be particularly fond of this habitat. The low-growing, white-flowered Ruellia patula is almost growing together with its mauve cousin R. prostrata and the taller and bright yellow Justicia odora. We find several species of Barleria in orange (B. prionitis subso. ameliae), white (B. lugardii) and blue (B. matopensis) but the shrubby clumps of Barleria mackenii with large, strikingly mauve-blue flowers trumpet their beauty above all others.

A grey-green suffrutex is dotting the ground in many places. Both the spidery flowers of many long white stamens and the warty green fruits clearly tell us it is a species of Capparaceae. A process of determination by exclusion leaves us with Maerua prittwitzii as the only candidate but strangely no literature mentions the habit as a suffrutex for this species.

One of the most spectacular finds of the morning must be Pterodiscus ngamicus. Grey and leafless for most of the year, this species in Pedaliaceae would go unnoticed despite its rather weird looks. It is only a small plant, less than 20 cm tall, but with a short and fat succulent stem, it looks a bit like a tiny "bonsai" baobab. Its fruits are 4-winged and succulent like rubbery Combretum fruit. Now it bears large flowers of an orange-red colour so intense, you can easily spot them from quite a distance.

We arrive at the large picnic site of Mandavu Dam and are able to get out, explore and have some breakfast. The site overlooks the largest body of water in the park and although varying enormously in size, it contains at least some water throughout the year. The site is still in good condition with toilets, shower, facilities to boil water and cook still all functioning well. Apparently a group of people has even camped here last night. They are obviously out on a game drive but the shaded viewing platform where we were planning to have our breakfast is still littered with their mosquito nets, chairs, plates and books to read. Like us they were obviously not expecting anyone else. The area is full of interesting plants. Some, although indigenous to this area, have obviously been planted here to adorn the site, such as clumps of the less common variety of Euphorbia cooperi, called var. calidicola, various Aloes and an unfortunately not flowering stapeliad. Other species occur here naturally. Right next to the platform, a large specimen of the Angular-stemmed Corkwood (Commiphora karibensis) shades the area. Straight out of the wall below the platform, a Large-leaved Rock-fig (Ficus abutilifolia) as always proves it capability of thriving where nothing else can. Jjust outside the fenced area we find the Pawnbroker-tree (Excoecaria bussei). The species has the typical 3-lobed fruit of so many Euphorbiaceae but these are the size of large plums. Even some the weeds at the platform are interesting and different. In the cracks between stones on the picnic site floor, a small, yellow-flowered composite catches our eye. It doesn't seem to be any of the weedy species we are familiar with. Thanks to the wondrous world of internet and Google we have since then found that Calyptocarpus vialis or Straggler Daisy, native to the southern USA and Central America, is a very likely candidate. If so this would be a first record of this species in Zimbabwe.

On the way back to Sinamatella we hope to enjoy some more of the beauty we found in the morning only to find that in this hot and harsh environment most flowers don't last through the heat of the day and have either withered of closed up until tomorrow. Only a Zambezi Fingerleaf (Vitex petersiana) is still showing us its lovely white flowers with a violet lip. We arrive in time for lunch and as it is too hot for fieldwork we decide to wait until later before exploring Sinamatella itself. We spend the afternoon hiding from the heat, downloading photos, working on the computer, making lists and checking specimens.

The gardens around the cottages and restaurant are no longer very well kept but this actually makes it more interesting for us. Indigenous species are creeping back into the flowerbeds, such as the delicate blue Megalochlamys hamata (Acanthaceae) or Sclerocarpus africanus (Asteraceae). It also satisfies our usual curious fascination with weeds. Just as in Main Camp, bar & restaurant are no longer functioning but everything is still in place. Tables and chairs are set out, even small oil lamps still hang from the ceiling but not a person in sight. It brings back memories of not too distant times when tea 'n' scones were served on the terrace while enjoying the view or a G&T in the late afternoon, watching a pack of dwarf mongoose running past at happy hour. It all has a great feel of former glory but it also still shows the potential, if only..... Then perhaps less cheerful images come to mind like scenes from The Shining.

By the restaurant veranda a vigorous climber is flowering profusely. The cascading showers of white flowers, covering entire clumps of shrubs, first make us think it a planted garden ornamental. Later, when we find the same species again on the rocky slopes below the campsite, we realize it must be an indigenous species and afterwards identify it as Stomatostemma monteiroae (Apocynaceae - Periplocoideae). The steep rocky slopes below the campsite and the cottages form a very different habitat and turn out to be a botanists paradise with other interesting species like the Northern Red-berry (Erythrococca menyharthii), a Dwarf Bush-cherry (Maerua parvifolia), Triplochiton zambesiacum, unfortunately without its splendid white and maroon flowers, and Marsdenia macrantha a climber with milky sap and creamy-white star-shaped flowers covered in velvety hairs.

The campsite clearly has not seen any clients for quite some time, nor maintenance for that matter. An impressive specimen of the Wooden Banana (Entandrophragma caudatum) towers over of the abandoned area with grass standing nearly 2 feet tall. Any intrepid camper who thinks that could make a nice soft mattress would soon painfully discover that small Acacia seedlings with large and vicious thorns are sprouting everywhere.

We wonder back towards our cottage and enjoy another night with all the simple comforts that working electricity brings, such as cooking on a stove, cold drinks from a fridge, lights to work by and even the cooling, albeit somewhat noisy pleasure of a fan. We can only wonder what our next stop will bring.

to be continued.