TREE LIFE

NOVEMBER 1989

 

MASHONALAND CALENDAR

Tuesday 7th November : Botanic Garden Walk.  Park you car at the Herbarium where we will meet at1645 hours for 1700 hours.  Tom Muller, we hope, will continue with Acacias.

Sunday 19th November :  Outing to Mazowe Citrus Estate by kind permission of the General Manager.  It is important that we all meet at the Dam Wall security barrier at 1000 hours so that car registration numbers may be listed, and we go through the barrier together.

Saturday 25th November : The official launching of Meg’s Key to the trees and shrubs   of the Mukuvisi Woodlands

Meg Coates Palgrave’s latest publication ‘A guide to the Trees and Shrubs of the Mukuvisi Woodlands has been published and is now on sale at a very reasonable $4.00per copy from Kim or Maureen.  It is an excellent booklet, well illustrated with Photostat copies of all the leaves in the key, together with a checklist, glossary and map of the woodlands.  You are all invited to the official launching at the Mukuvisi Kiosk (from the Mutare Road turn south into Glenara Avenue, cross the railway line and turn left into Transtobac road.  After 100m turn right into the main Mukuvisi gate).  We plan to meet at 1430 hours, have tea at 1500 hours and a short walk in the woodlands at 1600 hours.  Any donations of cakes for tea will be gratefully received.

 

MATABELELAND CALENDAR

Sunday 5th November 1989 :  We have found a place with leaves!  Meet at Ascot car park (lifts already arranged at 0830 hours.  We then proceed about 20km on the Johannesburg road to the Diana’s Pool turn off.  2km along there we come to Miss Isobel McCalman’s “Amalenda” where we park and walk about 20 minutes to a perennial spring and trees – morning only.

Sunday 3rd December 19189 :   the long awaited outing to Roy Stephens’ farm “Shumba Shaba Mkulu” 54 km out on the old Gwanda road (just beyond the Matopo Mission).  Meet at retreat Shopping Centre (lifts already arranged) at 0830 hours and follow the route via Matopos road, turn left to Fort Usher, right on to Old Gwanda Road and we will be led from there.  Three perennial streams, mystery trees and unusual localised ferns await us.

MATABELELAND NOTES

Parinari curitellifolia. Photo: Bart Wursten. Source: Flora of Zimbabwe

Parinari curitellifolia. Photo: Bart Wursten. Source: Flora of Zimbabwe

On our outing to the Quiet Waters Conservation Scheme of Falcon College near Esigodini, one of our members suggested that the song ‘Mad Dogs and Englishmen to out in the Midday Sun” would be altered to include the Tree Society – and we all agreed!!  At 34 degrees in groves of leafless trees it was a bit uncomfortable and but for our foresight on a previous visit of placing national numbers on selected specimens, we might not have even reached the magic figure of 45 trees for the outing.

The hairy caterpillar pods on the Ormocarpon trichocarpum were a safe bet, as was the squared stem of the Grewia flavescens and next to it the G.monticola and the new tiny leaves and flowers of the Diplorynchus condylocarpon, once broken off showed the sticky latex, which is always a good feature to show new members!  Our experts, Geoff Archer, Thora Hartley and Betty Blake were hard pressed to answer various queries, but all were agreed on the mabola plums from the Parinari curitellifolia which were duly sampled.  A friendly Greater Honeyguide pointed out the Kirkia acuminata and although small, the Euclea divinorum looked as if the leaves had been there forever.  The Faurea saligna were a bright spot on the landscape and some of the Burkea africana were getting the sprays of attractive flowers.  We puzzled over some dried up leaves, but later came upon a better example of the Vitex payos and down by the river several acacias were seen to be trying, A.gerrardii, A.karoo, A.nigrescens, A.rehmanniana and A.sieberana.  It was surprising to see the fruit before leaves on the Lannea discolour and we all agreed that the monkey oranges came from the Strychnos spinosa.  Morning tea break and an elongated lunch were taken in the attractively built study centre on top of the hill, and but for a 24 hour veld fire and the ever present heat haze we would have commanded a fine view of the countryside.

Lionel Reynolds, one of the committee members running this little gem of a conservation project, accompanied us on our walks and climbs and felt sorry for us and invited us all back to his shady lawn for drinks and showed us a Faidherbia albida which he had planted and it had grown to about 6 meters in just three years.

The Matabeleland Branch is sponsoring the new tree cards for Quiet Waters Scheme as we feel that this is a very worthwhile training project for various schools in the area to learn about nature under ideal conditions.  Animals are being introduced (we saw 5 kudu and tripped over a klipspringer). Nine tree walks have been cut and aloes planted – all in an electric fenced area of 220 hectares – we really must try to get back there at a reasonable time of the year to appreciate all the effort and enthusiasm generated by the Quiet Waters Committee and donors.

-Ken Blake.

 

BOTANIC GARDEN WALK

This month, yet another session of doing battle with acacias.  Tom can’t really see the problem of course, and he can certainly explain the differences.  All very well if one has leaves, flowers and pods to go by.

However, to simplify matters, the walk involved looking at the hook thorned species, which generally, although not always, have cylindrical flower spikes, as opposed to the balls of the straight thorned species.  Within this group, the species have varying numbers of pinnae and leaflets with leaflet size diminishing accordingly.  Acacia nigrescens (knobthorn) has the largest leaflets of all, there being only 2 – 3 pairs of pinnae, with one pair of leaflets.  The sharply hooked prickles are outgrowths of the epidermis, not modified stipules s is the case with straight spines.  The midrib of the leaf is also armed with curved prickles and the flowers are cream ‘catkins’.  Most distinctive of course are the knobs of the main trunk and branches.  The curved prickles become progressively raised over time and in older specimens protrude two or more centimetres from the trunk.  Some other species become knobby, but seldom to the same degree.

Acacia mellifera subspecies detinens. Photo: Sheila Gregory. Source: Flora of Zimbabwe

Acacia mellifera subspecies detinens. Photo: Sheila Gregory. Source: Flora of Zimbabwe

One such is Acacia mellifera subspecies detinens.  Its range also overlaps with that of A.nigrescens, but the flowers are white balls, an exception to the “hooked prickle catkin flower “ rule.  The other exception to this rule was A.albida which has straight spinescent stipules but catkin flowers.  Party for this reason it is now taken out of ;Acacia and renamed Faidherbia albida, Acacia goetzii also bears some resemblance to A.nigrescens, but it always has more pinnae and leaflets.  There are two subspecies, A.goetzii and A.microphylla, the latter being less common and having more, smaller leaflets.  A.goetzii is a true woodland species, and South of Masvingo gives way to A. burkei and A.welwitschii both of which it closely resembles.

The calyx of A.welwitschii is glabrous, as are the leaves petioles and branchlets, a feature that distinguishes it from A.burkei and G.goetzii,  the pods are also narrow.  The stipules on Tom’s one were still visible on the base of newly emerged leaves, clearly showing that the prickles are not modified stipules.

Acacia erubescens. Photo: Bart Wursten. Source: Flora of Zimbabwe

Acacia erubescens. Photo: Bart Wursten. Source: Flora of Zimbabwe

Passing on to A.erubescens, we find it to have many more leaflets and pinnae than the previous species.  The pinnae are relatively long,  being equal to or longer than half the midrib length.  This may seem a tedious feature, but it does distinguish this species from A.fleckii, which we saw later.  A.erubescens is a rather sprawling shrub, but its shape is apparently very variable according to edaphic conditions i.e. soils, water availability etc.  It is ‘infested’ with prickles and has cylindrical whitish flower spikes.

We looked briefly at A.caffra.  A look at most distribution maps will not show any occurrence in Zimbabwe at all.  One large tree near the old Bulawayo road near Harare has been known for some time, but the sceptics always considered it to be there by unnatural means.  However, it has now been identified from Wedza Mountain.

Acacia hereroensis also showed the hooked prickles that usually go with the spike flowers.  This is also an uncommon species in Zimbabwe occurring mainly in Botswana, and in one of two isolated localities here.  It could easily be mistaken for A.fleckii but for its longitudinally fissured bark.  Its leaflets are even more minute than those of A.fleckii, which we saw next.  The bark was greyish and peeling in ‘flecks’ – with no sign of the longitudinal fissures of A.hereroensis.  Most noticeable was the large single gland on the petiole.  It was young and green and each had exuded a tiny droplet of absolutely clear, colourless and extremely sweet liquid.  Though smaller than the head of a pin these tasted quite strong.  Surprisingly there were no ants or other insects to be seen!

Contrast the size of leaflets to A.erubescens mentioned earlier – here the pinnae are about 1/3 the midrib length.

Walking on to A.senegal, which still falls within the group with relatively few leaflets we were shown that the prickles occur in threes, a clear identification for this species.

We rounded off with a few of the “many leaflet” group within the hook thorn category.  Acacia galpinii has a wide distribution and is a large leafed species though with many leaflets and pinnae.  It has a purplish appearance, especially when in bud as the clyces and petals are purple.  When the flowers open the spikes appear yellow.  Acacia polyacantha (white thorn) is also very common, especially along rivers, and as a short succession tree of disturbed ground where it may form troublesome thickets.

Lastly we looked at S.senegal distinctive by virtue of its prickles occurring in threes, a very unusal feature in Acacias.  There are two subspecies, one vari. rostra, is usually a bush with short pods, the other var leiorachis is always a tree with comparatively long pods.

Our thanks to Tom, in the hope that we may have learned something more of this large and complex genus.

-C.Haxen

 

OUTING TO IGAVA FARM, SOUTH OF MARONDERA

Clerodendrum wildii. Photo: Bart Wursten. Source: Flora of Zimbabwe

Clerodendrum wildii. Photo: Bart Wursten. Source: Flora of Zimbabwe

Having cycled to Marondera I was not about to run around too energetically and so some of us had a quiet morning looking at what was around us.  Although the bush was dry and the weather hot we saw a surprising amount of interest.  We had stopped on a rocky outcrop with small trees of Combretum hereroense, C.apiculatum, Acacia rehmanniana, Brachystegia spiciformis and Monotes glaber.  Between these we found Clerodendrum wildii with ovaries that were swelling into a 4 lobed fruit.  We noticed the stinky leaves with red peticles.

There were a number of bushy Dovyalis zeyheri whose leaves often have characteristic leaf miner tracks beneath their cuticles.  Last month Prof. Wilkensen, who now works at the University of Botswana, visited Zimbabwe and gave a research seminar on the leaf mining Lepidoptera (moths).  Leaf miners are either flies (Diptera) or moths (Lepidoptera).  In general the miners immediately beneath the cuticle are more likely to be flies, moths tend to mine deeper layers.  Moths often leave a neat line of frass (the scientific term for larval faeces) down the centre of the mine track whereas the diptera have an untidy pattern.  This frass pattern is easily disturbed by rain – it then becomes unreliable.  The leaf miner in Dovyalis zeyheri is a fly as the pupal case has a distinctive bump on the one side.  Prof Wilkensen also discovered that although fruit trees may be heavily infested with leaf miners and these may appear unsightly the photosynthetic activity of the leaf is not affected so production is not reduced.  In fact in some cases the presence of the leaf miner stimulates the release of a growth hormone and so more leaves are produced.  Therefore total production of the tree is increased.

Carissa edulis. Photo: Bart Wursten. Source: Flora of Zimbabwe

Carissa edulis. Photo: Bart Wursten. Source: Flora of Zimbabwe

Carissa edulis were covered in the sweetly scented flowers characteristic of the APOCYNACEAE.  I expect my students to identify the family and then outline all the features which they may expect to find in that plant.  During a recent practical we stood in front of Tabernaemontana elegans and the students correctly identified it as belonging to the APOCYNACEAE.  Many features were listed but the possibility of toxic chemicals was ignored (toxins are synthesised in many of the APOCYNACEAE eg Nerium, Strophanthus and Acokanthera.  My prompt as to the possibility of toxic compounds was met with a smile and an explanation.  Milk intolerance is common in Zimbabwe, particularly amongst the Shona, and can be overcome by drinking sour milk products instead of fresh milk.  The sour milk produced in the communal lands often requires a double fermentation process using natural yeasts, this takes time.  Thus those students who used to herd cattle in their early youth they would steal the milk and add some of the milky latex from T.elegans, this curdles the milk rapidly.  So obviously the sap of T.elegans is not toxic.  The fruit of C.edulis are edible (as the name implies) and tasty but one must always be sure that you have not muddled the tree with the similar Acokanthera.  Another member of the APOCYNACEAE, Diplorhynchus condylocarpon, also grew amongst the rocks.  Other trees on the hillside included Steganotaenia, Indigofera rhynocarpa and Pappea capensis.

Back on the bus we were shown a branch that had compound leaves with an odd leaflet and an opposite arrangement.  Immediately one thinks of BIGNONIACEAE but this ws the exception – Fagaropsis angolensis,  RUTACEAE.  Around the margins of the leaflets were the many gland dots characteristic of the citrus family.  Another specimen was found at lunch time.  This was most exciting as we have only seen it once before on a tree society outing, also in the Marondera area.  We all had lunch in the tall musasa woodland that had Gardenia spatulifolia and Xaronphis obovata in full flower.

After lunch we boarded a trailer towed by a tractor and headed into the private game ranch on the farm.  We were fortunate enough to see impala, bushbuck, duiker and sable but these did not detract from the woodland in which magnificent specimens of Burkea africana were in full flower with delicate sprays that remind one of an oriental print.

We walked around a rocky area and found an Elephantorrhiza which I assumed to be E.goetsei.  Tessa was a lot more astute and took specimens home.  She discovered that the midrib of each leaflet ran along the edge and was not central – a distinctive feature of E.suffruticosa.  This tied in with the fact that the flowers were produced together with the leaves (E.goetsei flowers before the leaves appear).  I am sorry we did not examine it more closely.

Our return to the farmhouse allowed us to relax on the thick pile of emerald lawn and drink cups of tea kindly provided by our hostess.  We are most grateful to the Rutherfords for having shared their beautiful farm, provided the tractor, the tea and their precious time.  It was also good to meet up with our Marondera members once again.  Jack Reid and the Ferrars made a special effort to join us.

-Kim ST.J.Damstra

 

PROTEACEAE ATLAS :  There is an enthusiastic move to map all members of the Proteaceae on a quarter degree grid just as we plan to do for the trees of Zimbabwe.  This atlassing will be invaluable for future work on distribution maps.  If anyone in the Tree Society is interested, or knows of anyone who may be interested to help with this exercise could they write to Colin Tedder, Coordinator, the Proteaceae Atlas, 65 Mars Street, Kensington, 2094, R.S.A.  They will then receive free copies of the Atlassing Newsletter – a smart illustrated publication on real white paper.  We would dearly like Zimbabwe to be included in their mapping exercise and so would like to support their efforts as much as possible.  I have volunteered to be a regional coordinator for Zimbabwe.

-Kim ST.J.Damstra

 

MUKUVISI WOODLAND MEMOS:

I am honoured, Mr Editor, that you should ask me to make a contribution to Tree Life.  I have been studying the vegetation of the place since 1973.  It is rare for me to go there even now, and not find something new, or a variation on something old.

Familiar as I am with the Woodland I remain very aware that I am still much of a ‘new boy’ relatively speaking, and to act as an introduction to the Woodlands, to readers less familiar with this delightful enclave of the wild kingdom, I have asked Mr. R. W. Petheram to write a few words of his recollections.  Dick writes as follows:

Dear George, Our brief chat the other day about the Mukuvisi Woodland stirred a few memories, stretching back a long way.

I have a vivid recollection of the excitement of a barbell chase when in 1922 or 1923 the river flooded from a breach in the Cleveland Dam Wall and hoards of us kids, black and white, converged on foot and by bike on the Mukabusi drift, not far from the present rail and road coring on the way to Cranborne.  At the time, Cleveland was the town’s only water supply, but that was something for our elders to worry about.

Years later, in the mid 1930’s the river again featured in a person experience.  Our bachelors’ mess had planned a move to new quarters on New Years day, but a last minute snag left us roofless.  The mess boasted two trusty old model T Fords so we piled our clobber into them and headed for the Mukuvisi Woodland where we camped under odd bits of canvas for a fairly rainy, but amusing month.  Presenting ourselves at office each day in the conventional well pressed grey longs, white shirt with tie and sports coat (only the seniors rose to the affluence of suits for every day wear) was quite a challenge, but we usually managed to get there without msasa leaves in our hair or water berry stains on our collars.  If there was, in those days, river pollution from any factory we were unaware of it.  The woodland was delightful, not densely wooded, but appealing in its variety and its moods.  These seemed dictated in part by the weather and in party by communion with the river.  Our intrusion was a peaceful one, and the occasional hare and duiker appeared to accept it as such.   If we disturbed the bird life initially, it could not have been for long.  They seemed to chatter and exchange of views about our early morning showers from a rope tilting a four gallon container in the trees and to flit inquisitively in the late afternoon to see which of us was planning a night on the town.

These trivia are mentioned mainly as an admission that it simply did not occur to us in those day, that there could be any threat to that relatively unspoilt little haven.

About thirty years later though, in the late 1960’s Douglas Aylen brought us sorrowfully but firmly down to earth, he Douglas had retired from the staff of  the Natural Resources Board, but in a personal capacity was still very active in the sphere of conservation and conservation planning.  He was, among other things, a student of population pressures and modern living stress, and he could see more clearly than most of us the imperative need for the preservation, and if possible, the expansion of open spaces.

In November, 1968, after a great deal of preliminary work, he at last aroused in a wide cross section of individuals and organisations, a sense of urgency in the matter, he presented a 7.5 page paper at a two day national conference of the Rhodesia Council of Social Service.  His ‘Makuvisi Scheme’ as it was called, embraced the catchment area in general and the Makabusi Woodland in particular.  The scheme had already been endorsed by the Natural Resources Board,  and the Association of Scientific Societies of Rhodesia, the Natural Resources Society and, of course, the Tree Society, of which Douglas was chairman; and it was unanimously supported at the conference.  The specific references to the Woodland “close to this stretch of the River” described it as “some 600 acres of commonage containing a wide variety of large tree, perhaps the sole remnant of tree veld of this type”, and recommended that a large area of it be “preserved as a monument, a wild park, and for educational purposed”.

The cost of reproduction of this paper was enthusiastically borne by the Tree Society and the Natural Resources Society, to ensure a wide distribution.

The scene now shifts to the 1970’s.  I made an attempt to record it in Science News in March 1979 which reads in part “The Natural Resources Society was prominent in continuing the campaign in 1971, and it became evident in January 1972, from the newly submitted Town Planning Scheme that it was the municipal intention to carry out residential development in the Woodland area.  A meeting at the University under the auspices of the Natural Resources Society resulted in a unanimous resolution objecting to the municipal proposals and urging that the area be preserved for all time.”

In the Pitman Report issued in May 1973 (Judge J.B. Pitman having been appointed by the Government to conduct an inquiry) the objections were upheld.  It was evident from the report that this enlightened ruling could not be upheld indefinitely without clear evidence of continued positive interest in the Woodland, and it was not long thereafter that Mr. R. James, manager of the City amenities Department coined the phrase “use it or loose it”.

The Woodland was in fact being used continuously by clubs, youth groups, schools and individuals of all races, but the extent of its use was very little publicised.  In keeping with the spirit of this theme,  however, an advisory committee, chaired by the Natural Resources Society was formed in 1974, and served further to foster the concept of cooperative action among societies.  In 1975 and 1976 the Wildlife Society turned its attention to the project and produced a number of proposals for development.  It convened a meeting of a large number of organisations, including the Municipality and as a direct result, first a liaison committee and then a working group took shape under the chairmanship of Mr. Rudyard Boulton, members came from the ranks of societies which had recently become affiliated to the newly formed Conservation Trust. From all this emerged after a number of vicissitudes, a Makabusi Woodland Committee, with the following objectives :

a)         through the medium of the Conservation Trust, to attain a legal status as a non-profit          company to negotiate a lease with the City

b)         to draw up conservation and development plan

c)         to consider finance.

You and I,  George, were both members of that committee.  A lot of water has flowed down the River since that report was written, and many of our early tentative plans have been amended, and some do doubt improved upon.  As a subscribing member of the Makabusi Woodland Association, though not a very mobile one, I keep a little in touch with the events out there and the activities of a number of clearly dedicated people and, of course, the prominent influence of the Wildlife Society is not lost on anyone.

Reflecting on that, I must add that any emphasis on the Tree Society’s participation in the formative years of the Mukuvisi Woodland is not intended to denigrate the outstanding work of other societies such as the Wildlife Society, the Ornithological society’s most admirable activities, also come prominently to mind.  But it is an historical fact, that but for Douglas Aylen, there would probably be no woodland along the Makabusi any longer, and I think it is a matter of pride that he pressed his case so ably and resolutely, large from the Tree society platform, during his chairmanship, and also that we took up cudgels, you and I, from the same base, in later years.  With best wishes, etc etc  Dick Petheram.

The foregoing is, I think, a very adequate introduction to our present interest in the Mukuvisi Woodland illustrating the full Tree society background, I am not one to dwell on the past, however, I believe in this case, the historical background to this terribly vital conservation project in the heart of Harare is important.

-G.Hall

 

OBITUARY :  Tree Life records with regret, the death, during September, of Mrs. Judy Reid.

Judy and her husband Jack, were founder members of the Tree Society, and some time ago were awarded Honorary Life Membership, in recognition of their outstanding service and sustained support.  For many years, Judy was our Honorary /secretary.  It was at a time when the Society was involved in a lot of field conservation, and a lot of planning and organisation and sheer hard work revolved around her.  With Jack (for a time our vice President) she inspired others by example in projects such as the creation of the Lake Mcilwaine Arboretum and from their home in Highlands, nestling among the musasas she loved, she and Jack led weekly walks in the Mukuvisi Woodlands long before the Mukuvisi Woodlands Association came into being.

Known to us for her gentle humour and abiding love of the veld, she was, to others, a guiding light in her 25 years of compassionate work for the Blind (she was an expert in, and translated many books into Braille).

To Jack, her husband of 53 years, our deep sympathy goes out.

-R.W.Petheram

 

CHIKWENYA NOTES – SEPTEMBER/OCTOBER 1989

Deinbollia xanthocarpa. Photo: Bart Wursten. Source: Flora of Zimbabwe

Deinbollia xanthocarpa. Photo: Bart Wursten. Source: Flora of Zimbabwe

The Faidherbia albida are in full fruit and the curly pods are being consumed eagerly by the elephant and other game.  The Kigelia africana are now in full bright green leaf and the new ‘sausages’ fruits are developing rapidly.  The Combretum microphyllum has finished flowering and now there is a canopy of pale, straw-coloured winged seeds to replace the scarlet blossom.  The Trichilia emetica flowers are now over and are falling from the trees in showers.  The round green fruits of the Cordyla africana have started to form.  The Lonchocarpus capassa have bloomed profusely this year, with a mauve carpet of fallen flowers forming under the trees.  Croton megalabotrys and Xanthocercis zambasiaca are also in bloom.  The Oncoba spinosa are dotted with their ‘fried egg’ flowers, and are forming small green fruits.  Some of the Diospyros senensis have started to flower and put out soft new leaves, while others are still looking very dead.  The Cleistochlamys kirkii have started to show new leaves, and the flower buds are swelling at last.  The Cassine schlecteriana are in new leaf, and are also flowering.  The Securinega virosa are showing very small tight buds.

The Deinbollia xanthocarpa have their white scented star shaped flowers and the Baphia massaiensis are decked with sprays of pretty jasmine pea blooms.  The creeping Strophanthus kombe are adorned with their strange flowers, trailing the long tendril like extensions.  The yellow Xylia torreana pompoms are almost finished, as are the delicate Capparis tomentosa blooms.  We have seen one Coffea covered in white blossom but the others are still biding their time.  To date, 14.10.89. despite recent overcast weather, we have not yet had any rain.

 

SUNDAY 12TH NOVEMBER, 1989 :VISIT TO BALLY VAUGHAN

The Aloe Society has arranged a visit to this beautiful Game Park only 44 km from Harare at a reduced group entry charge of $10 per person and extend an invitation to any Tree members who may like to join them.  Bring $10, lunch baskets, hats etc. and meet at c

Chisipite Shopping Centre at 0900 hours.  We have to know numbers so please telephone Nienkie Weeks on 50055 for further details.

 

DICK HICKS  CHAIRMAN

 

 

 

 

 

 

Xylia torreana. Photo: Bart Wursten. Source: Flora of ZimbabweAdonsonia digitata. Photo: Mike Bingham. Source: Flora of Zimbabwe