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TREE
SOCIETY OF ZIMBABWE
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December 2003/ January 2004 JOURNAL
OF THE TREE LIFE THE
CHAIRMAN WISHES ALL MEMBERS OF THE TREE SOCIETY AND THEIR FAMILIES A
VERY HAPPY CHRISTMAS AND
A BRIGHTER 2004. FROM THE
ABOVE DATES YOU WILL HAVE NOTICED THAT THIS ISSUE OF TREE LIFE COMBINES
DECEMBER AND JANUARY AND WILL BE A LITTLE LONGER THAN USUAL. THIS IS BECAUSE MARK AND MAUREEN WILL BE VISITING OTHER PARTS OF
THE WORLD DURING MOST OF DECEMBER.
MASHONALAND CALENDARTuesday
2nd December. Botanic Garden Walk. Meet in the
car park at 4.45 for 5 p.m. The topic will be the family flacourtiaceae. Sunday 7th
December. This
will be our Christmas Social and once again Bill Clarke has invited
us to his lovely property ‘Val D’Or’ in the Arcturas area
Adele and Rob have compiled a quiz which should be a lot of fun
- there will be prizes. As is
usual at these Christmas functions we invite members to bring something
to share for tea. The
program hasn’t been finalised yet, but lunch will probably be after
the quiz and in the afternoon we could take a walk in the woodland. Directions. From
Harare turn off the Enterprise Road onto the Arcturas Road and continue
for about 26 kms. Beware of
the vicious speed humps outside the cement factory. Turn right into
Gardiner Road and continue along
this narrow tarred road for 4.7 kms.
There is a sharp turn to the left, at which point turn right
onto a Saturday 27th
December. As Mark will be away there will be no walk
on the fourth Saturday. Tuesday 6th
January. Botanic Garden Walk. Meet Tom in the car park
at 4.45 for 5 pm. Sunday 18th January. 49 Umwindsidale Road. Eleanor and Norman Dickens have a property on the Umwindsi
River and have kindly invited us to spend the day with them. Directions: Proceed out of town on the
Enterprise Road until you come to the Umwindsidale Garage at the turn-off
to Chishawasha. Take the next
turn to the left (shortly after the garage).
This is Umwindsidale Road. Follow
along it until you come to number 49. Bring your chair and lunch, to
arrive at 9.30 am. Saturday 24th
January. Mark’s
Walk will be in the Mukuvisi Woodland, in the Blatherwick Road area
which is a very interesting patch – especially at this time of year. Directions. Take the Chiremba Ave Road
out of Harare, turn left into Ford Road and meet at the Ford Rd/Blatherwick
Rd. junction at 2.30 pm. MATABELELAND
CALENDAR
Nothing has
been arranged for
December For details of the traditional New Year get-together
in Bulawayo please contact Jonathan Timberlake. Welcome donation
from PG Industries
Earlier in the year I wrote to a number of local companies
asking on behalf of the Tree Society for donations to enable it to continue
functioning and to carry out its various projects. We have now received
a donation of Z$50,000 from PG Industries. This is the first successful
response we have had. We are very grateful indeed for this sum, which
has strengthened our financial position and will help somewhat to ease
pressure on member’s subscriptions. Thank you, PG Industries! Mark Hyde BOTANIC GARDEN
WALK: 4 NOVEMBER 2003 Albizias, continued ... Tom once again tackled the question of albizias. We
looked again at some of the same species which had been rushed last
time and saw some we didn’t see last time. Maureen had kindly provided
photocopies of the write-up of the previous walk and this was helpful
as it enabled us to look up each species in its “group”. In each case,
we recorded the position of the petiolar gland, expressed as a % of
the petiole length from the base of the petiole. Albizia harveyi
was dealt with rather superficially last time. A very important character
is the very rough bark; this was particularly striking on a specimen
we saw near the restaurant but in fact less so on the first tree we
examined not far from the car park. The leaflets are slightly sickle-shaped
(falcate) and the pinnae are some way apart – features which separate
it from the much commoner Albizia amara. It occurs in both riverine
and woodland habitats in the lowveld and also ascends to higher altitudes
in alkaline soils. The gland was high on the petiole, c.60-80% of the
petiole length. A. brevifolia could not be found last time,
but several small trees were found on this occasion. The trunk and larger
branches bear lateral spurs with a swollen base which look a bit like
commiphoras. Leaflets are very small and the pinnae are widely spaced.
The gland is at about the mid point of the petiole. This is a low altitude
species and occurs on the schist belt at Kariba and commonly on kopjes
around Hwange. Albizia amara has relatively short stamen-filaments;
the clusters of flowers really do like shaving brushes. Digressing,
Tom mentioned that he only owned three high quality items: a badger-hair
shaving brush, a hairbrush made out of Siberian wild boar hair and handmade
crocodile leather shoes. The pinnae are close together (already mentioned
in the comparison with harveyi) and the bark is rough (like harveyi).
The gland is at about 1/3rd of the way up the petiole. It
is a very common species at both high and low altitudes, often occurring
in woodland. We next viewed the very large specimens of Albizia gummifera in the Garden. These
are very fine and were covered in flowers – but all were way out of
reach - and no ladies volunteered to climb them. Noticeable features
of this species are the smooth bark and the reddish flowers in the centre. Similar to A.
gummifera is Albizia adianthifolia.
There is no specimen in the Gardens but Tom listed the features which
distinguish it from gummifera, namely the rough bark, the absence of
a “heel” on the leaflet and the hairy leaves. Again we looked at Albizia antunesiana; the petiolar gland is exceptionally large and
right at the very base of the petiole. Albizia glaberrima
is a lowveld, riverine species. The pinnae have the largest leaflets
at the apex and their arrangement is a bit like duiker footprints. The
gland was between 1/3 and ½ the way up the petiole. Although this species
does occur in the Zambezi it is not common there; its greatest frequency
is in the SE of the country. Albizia versicolor
was in full flower and looked very beautiful with its large flowers
raised above the leaves. The gland position was relatively low: 20-25%. Albizia petersiana
has a characteristic red flush in December. The gland occurs at halfway. Albizia forbesii
has tiny leaflets; it is a species of triassic sandstones in Gonarezhou.
The gland is in a high position at c.70-75% of the petiole length. In addition to albizias, our attention was caught by
some striking species in flower. A bush of Gardenia
resiniflua (gummy gardenia) was covered in white flowers. Tom mentioned
that this is another lowveld species which is a one day wonder, so we
were I suppose lucky to catch it. Certainly, although I’ve often seen
the species in the wild, I’ve never seen it flowering before. The deep yellow spherical clusters of flowers of Acacia grandicornuta, arranged in long
spike-like panicles flowers, were very striking. Finally in darkening conditions, we came across the
strange, dark, liver-coloured flowers of Monodora
junodii. As usual, we
saw an enormous amount of interest and our thanks go to Tom for continuing
to provide this wonderful service to the Tree Society. Mark Hyde TREE SOCIETY
VUMBA TRIP: AUGUST 8TH -
12TH, 2003 The Tree Society visited the Vumba (sometimes called
the Bvumba) mountains over the Heroes weekend. This was a difficult
trip to organise (and I speak with feeling as the main organiser - at
least at the Harare end) mainly because of two problems, namely the
severe fuel shortage and the shortage of cash. Fortunately, John Bennett
came to our rescue. He not only sorted out accommodation for us in the
Vumba but he also arranged for his employer to provide some fuel for
us to enable us to get back to Harare and also was able to assist with
cash when time came to settle our bills. On behalf of the Society I
would like to thank Chris Donald of GMS for supplying the fuel. Friday August
8th
We travelled up in rather grey weather, stopping briefly
at Halfway House near Headlands. On arriving in the Vumba we drove straight
to John Bennett's cottage where we arrived in the early afternoon and
had a late lunch. We then identified a selection of trees which John
had collected near his cottage. John has written about these together
with other observations about the Vumba: TREES ON FRESHWATER, VUMBA
My move to Manicaland was prompted at least as much
by my fascination with low altitude areas as with mountains. I had not seen myself settling in the “mist
belt” of Vumba, at an altitude scarcely below that of Harare. If the Albizia
gummifera (schimperana?) canopy represents the crowning glory of
complex forest systems responding to abundant moisture, I was stopped
in my tracks on a recent visit to the lowveld, by that dramatically
different Albizia tanganyicensis. For me it reflected the stark beauty often
distilled under conditions of extreme stress.
This was the “real” Africa, and Vumba
the priceless exception that proves the rule. On the Heroes holiday trip to Vumba the most concentrated
learning curve for me was in the first 15 minutes. On the morning before
the group’s arrival, I had collected about 17 leafy specimens from plants
with which I had become familiar.
Meg explained these, all forest outliers, common in the grassy
to wooded areas between Eden Estate and the mountain.
Cussonia spicata
was confirmed, the gnarled old man of both the fire- and mist-swept
slopes and of the wetter, grassy hollows.
My heart lifted recently when I noticed
that a Cussonia, decapitated by a toppled wattle and deprived
of all foliage, was sprouting a new rosette of leaves from the top of
its spindly neck after 2 or 3 months.
(Whether the wattle sprouts again is an altogether darker and
more tragic matter.) Another inhabitant of more exposed places, and a remarkable
fire survivor, is Vangueria apiculata.
It is never very large, angular in form, and its bark has a deeply
reddish hue – its sparse leaves unmistakably of the Rubiaceae family.
Syzygium cordatum
is at the opposite end of the scale – an abundant and large tree marking
all the wetter spots outside of the rain forest.
I was struck when we visited the Bunga Forest, about 200m higher,
by how dominant and massive this Waterberry is, its leaves showing distinctly
red, within the top level of the forest.
A multi-stemmed Sapium
ellipticum grows out of the edge of a steep gully near where I hope
some day to build a house. It
provides useful hand holds when you need to descend to your dog caught
in a snare set along the stream. It
has characteristically drooping branches and black-stained undersides
to its leaves. Morella (Myrica)
is a smaller tree, occurring
across all the habitats. It
has a markedly light-coloured bark enclosing a “puffy” stem, but its
leaves are hardly serrated and with no trace of yellow, so presumably
ruling out M. serrata. (M. pilulifera?) I find
it a shapely tree, probably because I like trunks. Like Ochna, the leaf mid-rib is prominent above
and below. Ochna holstii, with translucent, thin leaves and yellow flowers, is
common on the edges of the forest. Among the shrubs and herbs that will probably not be
described elsewhere, as we visited only the rain forest, are Aeschynomene nodulosa…a legume with colourful
orange flowers, and Harungana
madagascariensis, both so numerous that I didn’t mind sacrificing
them when choosing a road in. Any
aloe or Tetradenia riparia in the way were transplanted. Rhus chirindensis was displaying its new, red tri-foliolate leaves. Gymnosporia (Maytenus) senegalensis has leathery
leaves and fearsome spines reminiscent of Dovyalis caffra. Toddalia asiatica is the name given to a pungent
green climber, with small thorns that visciously attach themselves to
your skin and clothes. No Tree Society visit to Vumba can gloss over the extent
of contamination by “alien” flora.
Intolerance of course is one of the less endearing of human traits
(especially among others!) But
“alien” here refers to much more than an occasional ill-judged siting
of a bougainvillea or jasmine. A
Vumba “alien” could as well be the lowveld flame Combretum
(paniculatum subsp. microphyllum). All are about as thoughtful as
putting a moustache on the Mona Lisa.
Now there’s a thought. I
must see whether the forest flame Combretum
(subsp. paniculatum) can rein in the rampaging guavas! Emotional diatribes are unlikely to cut much ice with
apologists for exotic invaders. So
I took some measurements. I
have discovered a re-growth rate of between 5% and 95% on wattle stumps axed within the last 5 months. Attempting to de-bark re-sprouting stumps while
standing waist deep in fallen logs is frustrating. But I feel this is a fray that one enters with
a chance of eventual success. A
few hours with a bush knife every week-end for the next 10 years? My skirmishes with Flowering Cherry however are decidedly
unequal. Every axed stump now
sports between 20 and 120 new shoots, some of them taller than me after
only 8 or 9 months. Infested
areas comprise some 150 stumps per 100 sq.m.
A typical area, 2m in radius will have 19 cherry trees, 2 each
of Ochna holstii and Clausena
anisata, plus a Gymnosporia
senegalensis, guava and something else.
From a distance the area now looks like a diverse and mature
woodland with Bridelia micrantha
in its russet colours, Erythrina,
Morella (Myrica), Albizia gummifera, and others.
But I have no doubt that in a few years these will have been
obscured, as they were a year ago, by a blanket of merrily twinkling
cherry leaves. Suppressing the temptation to use an expletive, I would
describe that rate of growth, as unnaturally rapid. Anyone needing convincing that stumping a mature
Cherry Tree is an altogether more daunting prospect than stumping a
mature guava, is welcome to visit Freshwater any time. I can provide picks, shovels and axes. It is curious that cherry is not regarded as
such a menace a mere 200m higher up or lower down. So why not bow to the inevitable? Accept that land has to pay its own way?
That what has once been put to Eucalyptus grandis, is forever after disturbed,
and should be retained for commercial uses, leaving one to concentrate
on preserving the pristine areas? That
if woodlots had been created within walking distance of Sakubva, the
miombo woodland in the lower Vumba might not now be disappearing daily
into town as firewood. But it was not rational analysis that fired up the
imagination in the first place. Was
it Pascal who wrote something along the lines that, “The heart has its
reasons, that reason alone cannot comprehend.”
Logic may be necessary to win over the sceptics. But the pity of seeing our wildernesses being
diminished before our eyes as invaders march across the landscape, is
something you either see and feel, or you don’t. It does raise the interesting question, why has natural
selection not produced any local species possessing a fraction of that
vigour? John Bennett *** Saturday August
9th and Sunday August 10th Meg Coates Palgrave has kindly
written up the next two days. The
nice thing about being asked to do a write up for a trip is that it
enables one to relive the experience and our trip to the Vumba was one
certainly one worth reliving. Poor Werner who broke his leg on the third
day may feel rather differently. We all wish him a speedy and full recovery.
When I have been to the Vumba in the past I have come away feeling a
little frustrated that I have not been able to identify as many trees
as I would have liked to, particularly those in the family Rubiaceae
and so I was determined to concentrate on them when I saw them. And
I have been able to name all that I brought back but one. Mark,
Werner, Gill and I stayed in a cottage and were joined by Liz and Tony for a meal most evenings. John
who had initiated the trip lives in a cottage not far away and that
was where we gathered each morning and were joined by Bart and Petra
and Tackie from the Vumba and Pat from Mutare. So we were a fairly small
group, happy to be sharing our interest in plants. The
first morning Roger also joined us and so we decided to take the opportunity
of his presence to explore his bit of forest just beyond Eden Lodge
which is just a few kilometres along the Essex road. Where we stopped
in an open spot, in lovely purple flower, were Polygala
virgata, happily also known locally as the pride-of-manicaland
or manica-pride. And then we were into the forest. We started with a
little familiarisation of some of the understory, species we were to
see over and over again. I keep saying all trees have labels on them
telling us what their names are. All we have to do is learn to
read the labels. Teclea nobilis, giant cherry-orange,
has a compound leaf with three leaflets, they smell quite strongly when
crushed and translucent gland dots can be seen when a leaf is held against
the light. This belongs to the citrus family and those translucent gland
dots contain the citrus oils as does Clausena anisata, maggot-killer with
pinnate leaves and a very pungent smell. We wondered if it really smelt
like aniseed or whether the Afrikaans name, perdepis translated as horse
urine might not really be more appropriate. I was quite excited to see
Keetia gueinzii, climbing
keetia, with the leaves subtending the branchlets smaller and almost
round, very different from the main leaves. This was something I had
recently read about and there it was demonstrating the label for us.
Mark showed us how we could always recognise Peddiea africana, green-flower tree,
a typical forest species with shiny green leaves. When a piece is picked
the bark strips off. We found some green-flowers, very sweetly scented,
they revived and lasted quite well in water. Later on in the weekend
we were to discover that this has another label without having to resort
to tearing off bits and pieces. It is obviously the food plant of some
insect which eats nice little rounds off the leaf surface leaving bare
patches. This was particularly obvious at higher altitudes in the Bunga
and Castleburn forests where we could just spot the dot as we walked
along. There
was a species we saw which we came across during our trip to the Honde
Valley last year, the wild ginger, Aframomum albiflorum, also known as
Madagascar cardamom. In the Vumba forests unfortunately there is a look-a-like
alien, Hedychium, also a member of the ginger family Zingiberaceae, which
really is becoming quite invasive. I get very upset about alien plants
when they become invasive just as the wattle and the pine have done.
Those two are obvious but there are others that seem to have crept in
almost unnoticed and are more or less accepted as being naturalised
and acceptable, as unfortunately this is becoming. It is quite attractive
when in flower, as is the wattle. One of the differences between the
two genera is that Aframomum bears its fruits
on the ground and Hedychium bears the fruits at the ends
of the stems. We eventually found some uneaten fruits of Aframomum.
They are red about 5 cm long with seeds in the middle. I enjoyed the
spicy flavour of the seeds when sucked but others found it not so pleasant. Forests
are often full of twiners and climbers and monkey-ropes one of which
was a Landolphia.
With a milky sap and opposite shiny green leaves with a wavy margin
was, as I have since worked
out, Landolphia
buchananii, apricot-vine. The difference between this and Landolphia
kirkii, sand apricot-vine which we saw the next day at a lower
altitude, I have read about but not really seen or understood before,
but now that I have the leaves of both species to compare, I can see
the difference. Firstly Landolphia buchananii is a species of higher altitudes and secondly
the lateral veins and net-veining are finely indented (valleys) on the
upper surface forming a net-work of shallow cracks. On the undersurface
the lateral veins are visible and slightly ridged but the net-veining
just looks a darker green. Landolphia kirkii on the other hand has very distinct pale greenish
cream net-veining flat or slightly raised on both surfaces. I must confess
to having to use a lens to see that detail. A milky sap and opposite
leaves in the tree world usually indicates that the tree belongs to
the family Apocynaceae as does this genus. The other interesting member
of Apocynaceae we found later in the Bunga and Castleburn forests was
Strophanthus speciosus, forest tail-flower.
I was surprised to see it there, there are no specimens from the Vumba
area in the Herbarium, but this is one of species that can’t be anything
else. It has a milky sap and leaves are in whorls of three and again
using the lens there are three tiny overlapping scale-like glands on
the inside of the bottom of the petiole. Another
liane which I have never come to grips with before is Tiliacora funifera, appropriately
called elbow-leaf because the petiole has a swelling and is bent just
before joining the leaf-blade. The leaves have quite a long petiole
and three distinct veins starting from the base. There
was a tree with leaves spirally arranged with toothed margins which
was coppicing freely from the base sending up long shoots. It’s name
did not jump into my head immediately but I was sure I should know it
and would come up with a name after lunch. That I was not able to do.
What I was thinking of was Aphloia
theiformis, albino-berry which coppices in a very similar fashion
and which we also saw. So as I write this I am afraid that is still
a mystery tree. The
characteristics of Rubiaceae are opposite leaves (in pairs) with entire
margins, and with a ridge going across to the opposite petiole with
a distinct stipule. One we saw and collected that morning was Rothmannia urcelliformis,
forest rothmannia. It did have its label, what I describe as the odd
third leaf or a single extra leaf in the axil between two shoots. At
the time I wondered if the leaves were too hairy to be the forest rothmannia.
We saw it again in the Bunga forest, this time with fruit and there
was no mistaking those hard round fruits about 5 cm in diameter which
take two years to develop and ripen after flowering. Someone
once asked why the Tree Society always looked at small things and I
seem to have concentrated on those, but let me assure you we were in
forest with the canopy high above our heads. To see the leaves we needed
to use our binoculars and that is very neck-straining when there is
so much to see at more or less at eye-level.
We walked under a liane with aerial roots just like those of
a fig, a liane whose leaves could not be reached but through the binoculars
they looked rather like those of a Rhoicissus
probably Rhoicissus rhomboidea, glossy grape, or as someone suggested ropewood
grape could be a good name for it. Mark later found some leaves at reaching
level for me to see. They certainly are very different from the familiar
Rhoicissus tridentata, bushman’s grape. Both species are essentially
climbers and have tri-foliolate leaves, the lateral leaflets have a
very asymmetric base and the midrib going up one side instead of being
in the middle, but the ropewood grape has leaflets with a pointed apex
and the margin with up to six distinct teeth each up to 2 mm long and
sticking out. The leaflets of the bushman’s grape have leaflets with
a square to rounded apex and 3 to 18 teeth, each tooth ending in a thin
point. And
then we reached a proper fig, a huge strangler with aerial roots from
the branches as well as the trunk, roots often reach the ground and
form pillar roots so that they sometimes look as though they are propping
up the branches. This was a really big one which we decided must be
Ficus rokko, rokko fig.
This species was part of the Ficus natalensis complex of the first
1977 edition of Trees of southern Africa and part of the Ficus
thonningii complex of C.C. Berg in Flora Zambesiaca but
is now happily and distinctively recognised as its own species being
very much a tree of forests and forest edges. What separates this from
the other forest species of fig is that the others all have leaves with
a distinct pair of lateral veins starting at the base and this doesn’t. After
lunch back at out cottage we made out way to the forest below Eden Lodge,
one which I have had the pleasure of exploring before. I missed the
path I had meant to take so we went right through the forest and then
came back along the planned path in the opposite direction to the one
I had originally intended to take. I was actually glad about that because
to me the highlight of the afternoon was a group of spiny tree ferns,
Cyathea manniana and that group is
much better viewed from the side we did eventually see them than if
we had approached from the other side. On the bank just above the spiny
tree ferns was a Myrianthus
holstii, reported as having leaves that fall with an ‘audible
plop’. Having come upon the tree ferns which were a lovely sight, slender,
several metres tall and often in groups and the sun just touching some
of them and there was quiet for a few minutes. A couple of people were
taking photos, the rest of us just enjoying the magical scene until
Gill asked if we were all waiting to hear a Myrianthus leaf fall with
its audible plop. Much laughter. We didn’t hear that but we did see
the surrounding vegetation festooned with fallen leaves. These are digitate
with five to seven large leaflets, dark green above and much paler to
almost white below. Previously
we had seen another tree fern which I had always assumed to be Cyathea
dregei, the common one or grassland tree fern with which we
are all familiar. Someone said they thought it was Cyathea thomsonii, thomsons tree fern.
I was the original disbeliever in no uncertain terms as I was so sure
that that was so rare I would never ever see it and frankly I had even
wondered if it really was different from Cyathea dregei. By the end of the four
days I had been convinced that it could indeed be Cyathea thomsonii and I
had seen it several times and that the two species are different and
distinguishable. There are several
reasons. This one was growing along the streams in deep shade. Cyathea
dregei is a grassland species usually in the sun. I was shown
a frond of both species to compare. The leaves of Cyathea thomsonii have pinnules with
only one row of sori on each side of the midrib while those of Cyathea
dregei have three or four rows as, I have since discovered,
is illustrated in Flora Zambeziaca tab 21 page 73. Having looked up the Red Data List for something
else I see that for Cyathea thomsonii it says “Site: northern
Vumba, Bikita. 'Not known if
it is still there, less than 25 individuals were seen in the late 1970's.
The habitat is probably stable but not protected.”
I don't know whose comment that was and if it also applies to
the Bikita record. And having also read what Keith said and I did not
change, I can see hairs on the undersurface of the leaves of Cyathea thomsonii, with a lens of course,
and which the leaves of Cyathea dregei do not have. I have
subsequently asked John Burrows who confirmed that he knew of several
localities for Cythea thomsonii saying that as it is so similar to Cyathea
dregei it may well have been overlooked elsewhere and so determining
it’s red data list status could be difficult. I do know that Tom has
tried several times to transplant it without any success and if Tom
can’t do it no one can. But with the success that nurseries are having
growing tree ferns these days this would be the best way of trying to
acquire one if any one feels they absolutely must have one. The other
doubt that was very strongly expressed was whether Cyathia capensis really exists in Zimbabwe. I have a note that
in Zimbabwe it occurs in high altitude moist forests and I am sure that
I have seen it at Nyazengu at the base of Nyangani mountain and the
altitude at Vumba is not much above that of Harare so it probably does
not occur there. Two of the other ferns that I recorded were Blechnum attenuatum and Marattia
fraxinea, both of which occur in wet areas in deep shade in
forest. Bart pointed out that Marattia is so fussy about habitat
that it was growing on one side of the path (the side next to the stream)
but not on the other dryer side. Other
trees which I recorded that afternoon were Embelia schimperi, another scandent
species, this one climbing by means of hard persistent lateral shoots.
The leaves are slightly fleshy and have little elongated translucent
glands seen clearly with a lens. Ficus craterostoma, forest fig is always
recognisable with the leaf apex very blunt or almost square (truncate),
sometimes even concave. Cephalanthus natalensis, strawberry-tree,
so called because the fruit are small capsules clustered together somewhat
resembling the fruit of a strawberry. We were there at the non-fruiting
time so did not see the fruit. This a member of the family Rubiaceae
so has leaves in pairs (opposite) but they are distinctive, being small
shorter than 5 cm, ovate or egg-shaped and the petiole is slender, kinked,
and often tinged with pink, the colour running into the midrib. Another
member of the family Rubiaceae was Tarenna pavettoides, which I thought
I would always recognise after our trip to the Honde Valley, but I had
to be reminded. The leaves are typical of the forest, quite big, dark
green with a drip tip, but it does have a label, on each branchlet there
is at least one pair of leaves that are distinctly different in size.
Another plant with leaves in the pair different sizes that we saw in
the understorey in Bunga Forest was Sclerochiton
harveyanus, blue-lips, but that has much smaller leaves with
the margin irregularly toothed and belonging to the family Acanthaceae.. Going
back to Rubiaceae a genus which showed variation between the altitude
of the top of the Vumba around the Bunga forest and the altitude at
Eden Lodge was Psychotria.
Psychotria
mahonii we saw that first day. The leaves have up to ten pairs
of lateral veins which are very distinct and the undersurface is quite
often hairy. Psychotria zombamontana we only saw on days three and four in
Bunga and Castleburn forests. These leaves have more than ten pairs
of lateral veins and are hairless. I have just realised that there is
another difference. The inter-petiolar stipules are up to 1,5 cm long,
but those of Psychotria
mahonii are divided into two lobes whereas the stipules of Psychotria
zombamontana are undivided. One of my problems has always been
how to distinguish between Psychotria and Oxyanthus as they both have big leaves
with prominent lateral veins. The leaves of Psychotria are decussate,
one pair at right angles to the next while those of Oxyanthus are all in the
same plane. The other interesting difference is that while Psychotria
bears the flowers at the ends of the stems Oxyanthus bears the flowers in clusters
in the axils of the leaves with one cluster per node on opposite sides
of successive nodes. I know the problems associated with having to wait
until the plants flowers, but this position of the flowers is a feature
that can probably be visible for quite a long time, first as buds before
flowering and then as fruit after flowering. On
the second day, Sunday we went down the Essex Road stopping at various
places on the way, one group even got as far as the Burma Valley and
bought bananas. At one of the places we stopped, just before we turned
off the tar, I found a scandent climber with opposite leaves and the
branchlets almost bent backwards to assist with climbing. I rushed back
to my book and keyed it out as Tarenna
junodii, very exciting. I even found a specimen with some flowers
on. When I got home I took one look at the specimen I had collected
and realised I had made a horrible mistake. The flowers on the specimen
were in the axils of the leaves and Tarenna bears their flowers at the
ends of the branchlets. I have gone back and checked my key and I think
where I went wrong was I presumed the leaves were small usually 3 to
5 cm long whereas in fact they are many leaves longer than 5 cm. When
I followed the key the correct way I came up with Psydrax kraussioides, climbing quar,
which it proved to be. Not a very good start, but a good lesson. It
might even have been ‘finger-trouble’ in computer parlance and I just
took the wrong route. A little
later Mark emerged from a clump of bush on the side of the road clutching
a twig of what he said was Mussaenda arcuata, forest-star, with
fruit. I was most impressed
that he knew what it was. When in flower I always recognise it. The
flowers are yellow with a star of brown hairs in the middle. But the
rest of the time it is, or rather now, was a problem. The leaves have
a very long petiole, up to 2 cm or even longer and most species in Rubiaceae
have a petiole much much shorter than that. So that is a good tip to
remember. At
the same stop Mark picked a leaf of what he at first thought might be
a Senna
but actually looking at the leaf which was pinnate (like a feather with
a thing in the middle and bits coming of along the side), it had the
leaflets alternate and ending in a single one so we decided it must
be a Dalbergia and it has proved
to be Dalbergia lactea, large-leaved climbing dalbergia. There are several
species of Dalbergia with a tendency to become scandent using other
trees for support and climbing by means of coiled branchlets. This one
has oblong leaflets with the tip or apex rounded and notched. Right
down at the bottom, more or less on the Mozambique border we were back
into bread and butter country. I always think of forest as cake and
woodland as bread and butter. This was very special bread and butter.
The Brachystegia
was Brachystegia
utilis, false mufuti, and there were both Uapaca sansibarica, lesser mahobohobo and Uapaca kirkiana, mahobohobo.
There were also the familiar Antidesma venosum, tassel-berry, Dalbergia
nitidula, purple-wood dalbergia and Pseudolachnostylis maprouneifolia,
duikerberry, all that I consider woodland trees but in among them were
forest species as well. Two small leaved Rubiaceae; the first Coddia rudis with the leaves
broadly obovate (like an upside-down egg) with the base running down
the petiole, probably correctly found here in higher rainfall woodland;
the second Canthium
ngonii, manica spurred canthium, the leaves in pairs at the
end of tiny little spurs-branchlets which are also in pairs. The leaves
are supposed to smell pungent when crushed. I am afraid that is subsequent
information and I did not know to check at the time. When
I wasn’t sure of the identity I put a specimen of leaves in the big
plastic bag hanging from my belt. These of course all had to be put
into the press but when I got back to the cottage I was too tired to
deal with them in the evening and got up early in the morning to do
so. Mark, on the other hand, who also had collected specimens into a
big plastic bag is a night bird and he dealt with his after supper and
sometimes late into the night. There
were some leaves that I collected which I noted as ‘opposite big shiny’
which I thought must be Rubiaceae as they had a ridge between the opposite
petioles and an interpetiolar stipule. It was only when I was having
a really good look at them that I spotted that the margin of some of
the leaves were slightly serrated around the apex and so was the Rubiaceae
look-alike Cassipourea.
This one was Cassipourea gummiflua, large-leaved onionwood, which has leaves
slightly to distinctly toothed. Cassipourea malosana, onionwood, had
presented no problems because that has the margin of the leaves with
conspicuously hooked teeth. The wood of some species is supposed to
have a strong smell of onion, hence the common name. It
is very frustrating to be able to put something into a family or genus
and not be able to give it a name immediately, but on
getting home it is quite satisfying to be able to work out the
identification and then confirm it in the Herbarium. There were several
with distinctly alternate leaves, distichous is the scientific term,
i.e, leaves on opposite sides of the stem but arranged alternately,
or one could say that they are all in the same plane and so lie flat.
One such was obviously a member of the family Annonaceae with leaves
slightly blue-green on the undersurface. I think I must have had a mental
block, because occurring in forest it couldn’t be anything else but
Uvaria lucida, large cluster-pear.
Alternate leaves, stems without stipules or stipular scars and the growing
tip at an angle to the axis of the stem is characteristic of Annonaceae
and also of Ebenaceae in which family is Diospyros, another one I needed to
get home before I could identify it. There were two options Diospyros
abyssinica, giant jackal-berry or Diospyros ferrea, bristle-fruit jackal-berry.
Again I checked in the Herbarium and decided we must have been seeing
the giant jackal-berry Diospyros abyssinica, albeit still
young because by the time I checked all the leaves on my specimens had
all dried and turned black as were all the specimens in the Herbarium,
while those of Diospyros
ferrea were of a much thicker texture and a sort of dull greyish.
That doesn’t really help in the field (or forest). The ideal is to be
able to put a name to a tree immediately. Diospyros ferrea has furry growing
tips and the young leaves are a coppery green. Diospyros abyssinica has
hairless growing tips and the young leaves are reddish. This is one
of the tallest trees in Chirinda forest but in the Herbarium there are
also specimens from both Vumba and Nyanga so I shall be making a correction
to the map in the book. One
of the surprises was the little Diospyros natalensis and it is different
from the Diospyros nummularia that we get in our rocky koppies. That has
round leaves and the one in the forest had elliptic to ovate leaves.
I looked at all the specimens in the herbarium and that was absolutely
consistent. So I am quite happy that we have both species in Zimbabwe,
even though White found difficulty separating them. There
was one tree with spirally arranged leaves with an entire margin that
had us foxed for most of the trip. It was only on the last day as we
were going into the Bunga forest when we found one with little white
fruit on it that we realised that it was Maesa lanceolata. A tree which we know
perfectly well when the leaves have a serrated margin. The book does
say ‘occasionally entire in forest specimens’. I have
never been very comfortable that I could positively identify the different
species of Dracaena. We saw them particularly in the Bunga forest on
day four. And those were, of course, Dracaena fragrans, small dracaena,
being in the understorey and with leaves on the top half of the of the
single stem. The were big broad, strap-like leaves more than 4 cm wide.
The other two indigenous species are Dracaena steudneri, northern large-leaved
dragon-tree, also with strap-like leaves more than 4 cm wide but those
plants tend to be more palm-like sometimes developing a few branches
at the top with the leaves in rosettes at the ends of the branches.
Dracaena
mannii, small-leaved dragon-tree has much narrower leaves, less
than 4 cm wide and is usually a much branched small tree, usually occurring
singly. Interestingly what is known as dragon’s blood is a resinous
exudate used for colouring in varnishes and lacquers and was known to
the Ancients who used it to stain horn to resemble tortoise-shell. This
exudate has been obtained from some species of Draceana. Day
three was ferns day and Bart and Petra lead us and we looked at many
ferns and I duly ticked names and hoped I would remember the names and
recognise some of the ferns. But there were too many for a beginner,
I enjoyed hearing about them but, I am afraid I soon got lost in trying
to learn them. We had a long walk in the Castleburn forest. That can
be described as being a wet side of the forest and from a tree point
of view was magical. However our walk on the fourth day was in Bunga
forest and because we were on the dry side of the forest there were
only two ferns, so I was able to come to grips with them, learning the
names and recognising them and being able to give them a name every
time I saw them. Asplenium sandersonii is a delightful little fern, growing on
trees or rocks with once-pinnate fronds, the pinnae or leaflets are
obovate with four lobes around the apex. What really intrigued me was
the fronds arch and grow from a bud at the end, so it spreads rather
like the garden plant that I know as hens-and-chickens. The other one
was Pteris catoptera. This is
a bit more difficult to describe. The fronds are three-pinnatifid. In
other words it looks like a bipinnate leaf but pinnules on the bottom
pinnae have divided again and also become pinnate. The frond looks like
feathers on a feather but the bottom feathers also have feathers on
them. I hope you see what I mean and if you are in Bunga forest that
you will be able to see and recognise these ferns too. And
I hope these notes will also help identifying the trees at the Vumba,
and that next time having had the opportunity to have a really good
look and do a follow up they will help me too. I have also been able
to update my key and have thoroughly enjoyed the whole exercise. Thank
you to all for their contributions and companionship. Meg Coates Palgrave Monday August
11th In the morning, we met at John's cottage (our standard
meeting point) and set off up the Essex Road heading for the main Vumba
Rd which would take us to the Bunga Forest and Ndundu Lodge. On the
way we stopped to look at a large roadside fern growing beneath a small
tree. The tree turned out to be of interest: Neoboutonia
macrocalyx. This has large
almost circular leaves and a very reliable spot-character: the underside
of the leaves are covered in stellate hairs. I've only seen it before
deep in the Bunga Forest so it was a little surprising to see it growing
on an open roadside. Our next stop was at a layby on the main road. (It
is the one with a picnic site, a very tight bend in the main road and
a bridge). From there we walked back along the road looking at both
the ferns and the trees. For me it was an absolute pleasure to have
Bart and Petra Wursten to identify the ferns and explain some of the
features and differences. For example, two species of "Lycopodium" were growing on the roadside
bank. I've put the genus in italics because there is a tendency to split
the species among different genera. One, Lycopodiella cernua, has
small upright branched stems which bear small deflexed cones at the
branch tips. The whole impression is somewhat like a small Christmas
tree; the other, Lycopodium clavatum, has longer more prostrate stems which occasionally send
up a stem with 1-3 cones. Vernonia wollastonii, a weak semi-climbing composite was everywhere at the
edges of the forest. Also at this point were two very beautiful species
of Acanthaceae. One was Isoglossa
mossambicensis growing by the road at
the edge of the forest. This has pale flowers with prominent orange
markings. Also present was the, in many ways even more striking, herb
Mimulopsis solmsii. There was less of this and only one bit was in flower so
it was actually less impressive on this occasion than the Isoglossa. Mimulopsis is said to flower gregariously. What is
said to happen is that the plants all flower simultaneously, produce
copious seed, die back completely. Then, over the next few years, the
plants grow again until they again simultaneously flower. This is known
as a plietesial flowering cycle. Various species of Acanthaceae do it
as also do some species of bamboo. When we visited Seldomseen the next day, the forest
was full of a tall (up to 2-3 metres) Acanthaceae, none of which was
flowering. I *believe* (but could be wrong) that this is Mimulopsis and that it is approaching its point of simultaneous flowering.
It is one of those things, if one ever lived in the Vumba, could form
the basis of some quite simple but fascinating research. Two, I hope interesting, plants were re-collected in
the very wet part of the layby (it is
about 6 years since I first saw them), namely a species of Sigesbeckia and a striking blue-flowered
Plectranthus. I still have
to find names for these, but I hope that they are both species of interest. On we went, stopping briefly at the Bunga Forest to
be shown some ferns, to Ndundu Lodge. There we had lunch. In the afternoon
we walked from the Lodge towards the bottom end of the Woodlands Road.
The path at first went through some rather dull areas which had been
hammered by Cyclone Eline (although even here we kept seeing things
of interest). We also were shown some Cyathea
manniana (spiny tree ferns) on which were
growing the characteristic epiphyte, Asplenium
hypomelas. We emerged at the bottom into an open area in which
some development had been taking place and from there entered another
forest. This turned out to be the most interesting piece of forest we
saw during the whole weekend. It is an absolute must to revisit this
again whenever we return to the Vumba. Sadly, I have not had time to
get names for all the things we collected - I hope to add this at a
later date. Certainly here were Chrysophyllum trees, probably gorungosanum, Strophanthus speciosus,
Schlerochiton, Rytigynia etc. Some of these have been covered by Meg in her write
up. At this stage, the density of exciting species was
such that some of us got a bit behind the rest. We (the tail) emerged
from the forest into a quite different habitat of Brachystegia
woodland and grassland in a rocky setting and with a magnificent view
towards the Himalayas to the south of the Vumba. It was at this point that Werner stepped into an innocent-looking
hole and did some quite serious damage to his leg. Even today, which
is 3 months later, the leg is still not entirely better. On the whole
we have had few injuries or problems on Tree Society outings and one
is inclined to forget that it can happen. The position was that Werner
could not walk on the damaged leg, we were some way, maybe 500 metres
from the road, and to get Werner out of there would involve getting
him through the rocky boulders, up into the forest and along the forest
path. Fortunately, Bart had his cellphone (and we were in
an area where there was coverage). He phoned Ndundu Lodge and an assistant
came out and brought a vehicle as close as possible. Then, taking it
in turns, two of us supported Werner as he hopped on the one good leg
back to the car. Then back to Ndundu Lodge for some drinks before a
very welcome fire. Tuesday, August
12th Werner decided to remain at the cottage today. The
morning was spent in the Bunga Forest. We parked our cars at Colin Saunders'
house and walked from there. One of the most interesting things was
how open the area had become; once again this is the effect of Cyclone
Eline. In the afternoon, we visited Seldomseen. This is a
familiar stamping ground for the Tree Society and I don't think we saw
anything new. Once again, the forest was much more open than I remember
it - probably because big trees were taken out by the Cyclone. It was
also full of the Mimulopsis , as we have already discussed. One genuinely interesting thing was a specimen of Brillantaisia subulugurica behaving as a tree. We took a picture of it with Meg
standing by it. This is a new species for the 4th edition of Coates
Palgrave! After the walk we spent some time admiring the views
from the lowest cottage (Crimson Wing) and then toiled up the steep
drive where we were kindly given tea by the manager and his wife. ***** All in all it was a fascinating few days and I would
like if possible to revisit the Vumba early next year. My thanks go
to John Bennett without whom the trip would never have happened. Very
special thanks must also go to Bart and Petra who assisted in so many
ways with local advice, including lunch at the lodge on two days, support
to rescue Werner and of course information about ferns, orchids, trees
and the Vumba in general. To Werner, I would like to say I am sorry the trip
turned out badly! But also to thank him for talking about and for naming
the orchids we found. I'd also like to thank Meg Coates Palgrave who
was our official leader on one day and co-leader on several others and
in particular for providing so much information over the trip. Mark Hyde Ann Bianchi is very kindly donating 20 trees to the
Tree Society to help raise some much needed cash. If you would like a particular tree let any of the Committee members
know and we will try to arrange it for you. Thank You Ann.
COMMITTEE MEMBERS' CONTACT TEL. NUMBERS Harare Mark Hyde Home 745263 Rose Greig Home 490250 Lyn Mullin Home 747169 Eva Keller Home 339368 Maureen Silva-Jones Home 740479 Bulawayo Jonathan Timberlake Home 286529 The Tree Society's e-mail address is Support the Tree Society Click here... Previous issues: Aims and Objectives - Monthly
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