Botanical Journal of the Linnean Society, 74: 279-288. With 2 figures
April 1977
Some observations on the cycads of‘
Central Africa
D. HEENAN
Cycad Garden, P.O. Box 77, Pigg’s Peak, Swaziland
Accepted f o r publication December I 9 7 6
The results of two expeditions t o Central Africa to collect and study cycads, mainly
Encephalartos species, are presented. Further morphological information o n the living plants
growing in their natural habitats is given, together with new localities. Species delimitation is
reassessed.
K E Y W O R D S :-Encephalartos
phytogeograp hy.
hildebrandtii-Encephalartos
laurentianus-morphology-
CONTENTS
Introduction
. . . . . . . . . . .
Observations
. . . . . . . . . . .
Cycas thuarsii . . . . . . . . Encephalartos barteri
. . . . . .
E. septentrionalis
. . . . . . .
E. hildebrandtii
. . . . . . . .
E. laurentianus
. . . . . . . .
E. tegulaneus
. . . . . . . .
E. poggei
. . . . . . . . . .
E. bubalinus
. . . . . . . . .
E. grams
. . . . . . . . , .
E. manikensis
. . . . . . , .
Imperfectly known species of Encephalartos
Encephalartos sp. ‘ A’ . . . . .
Encephalartos sp. ‘B’ . . . . .
Encephalartos sp. ‘C’ . . . . .
Conclusions
. . . . . . . . . . .
Acknowledgements
. . . . . . . . .
References
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INTRODUCTION
It has appeared obvious for some time, from information received from the
field, that the published accounts of African cycads by Melville (1957), Turrill
& Milne-Redhead (1958), Hall & Jenik (1967) and Dyer & Verdoorn (1969)
require updating.
With this in mind, two expeditions were launched in 1973 and 1974 under
my son’s leadership. The object was t o obtain specimens for various collectors
and institutions and to record pertinent field notes.
Conditions at times were exceedingly difficult, particularly in Tanzania and
279
280
D. HEENAN
Zaire. At the time of the first expedition Uganda was also a closed country,
and though governmental permission had been received, travel was not easy.
Permission could not be obtained to visit the sites of E. marungiiensis Dewed
(Malaisse, 1969; Lisowiki & Malaisse, 1971) and E. schmitzii Malaisse in
Eastern Zaire and there were insufficient funds t o continue travel to the
Kwango River on the Angolan/Zaire border, the main site of E. laurentianus De
Wild., so that certain comparisons unfortunately could not be made.
OBSERVATIONS
Cycas thiiarsii Gaudin
This species was originally described from Madagascar. Its presence o n the
African Continent as a native has been implied (Turrill & Milne-Redhead,
1958). After a two-month extensive search from the Zambezi River delta to
Ncala (14"35'S, 40'45'E) no specimens were found in nature. There were
many in cultivation in towns and gardens, but it appears that natural stands, if
they occurred, have been eradicated in this part of Mozambique by the
expansion of agriculture, mainly coconut plantations. Isolated clumps were
found from 10 km south of Dar-es-Salaam northwards t o Lamu in Kenya along
the coastal plain.
Encephalartos barteri Carruthers
After extensive searches in North-west Uganda in the area from which a
reputed specimen came, no trace of this species could be found. The record
comes from a Ugandan Forest Department collection 'F.D. 205 5' which was
recorded by the collector as being from a homogenous population, although
from different plants. It was identified at Kew as male cones and four
photographs of E. septentrionalis leaves, and one photograph of E. barteri. In
view of the extensive search conducted it is probable that E. barteri is restricted
t o West Africa unless further uncontroversial evidence t o the contrary comes to
light.
Encephalartos septentrionalis Schweinfurth
The areas approximately 5 km W.S.W. of Moyo (3"38'N, 31"40'E, alt.
+ l o 0 0 m) and 7 km N.N.E. of Lotuturu in the Imatonz Mountains. (3' 50'N,
32" 55'E, alt. to 1850 m and over) were visited in the N.W. and N.E. of Uganda
and also the adjacent area in the Imatong Mountains on the Sudanese side of
the border. It is interesting that these two colonies are separated by a distance
of 140 km and are located on either side of the Nile River. In both cases the
plants were growing in rocky outcrops and were partially protected, being in
forest reserves. The caudices of the Imatong colony were noticeably more
compact (altitude?) and the plants taken for specimens travelled better and
transplanted more successfully than those collected from Moyo. It was also
observed that after rain the Moyo locality specimens exuded copious quantities
of the jelly-like substance common to all Encephalartos; in fact far more than
any other known species. The exudation from the Imatong specimens was
CYCADS O F CENTRAL AFKICA
28 1
noted to be very slight under identical conditions, when both were in
cultivation side by side.
Soil samples taken in the Imatong Mountains indicate an average pY factor
of 5.9 with a slight deficiency in phosphorous. Soil composition was 55% sand,
21% silt and 24% clay.
Observations in the Imatong Mountains cast doubts on Melville’s theory
(1957) regarding depredations by baboons. Female cones in this area had been
damaged by these animals but there were no signs of ingestion, such as partially
chewed seed or defaecated shell segments. Comments by Dyer & Verdoorn
(1969) on this matter and also their remarks regarding fire and the depredation
by man appear much nearer the truth. In this case a possible theory is that the
cones are simply used by the baboons as ‘toys’. To support thls theory, a good
crop of seedlings was noted in the same area and few seeds had actually been
damaged, However, various species of hornbill and parrot are reported in this
locality-a fairly wide distribution-and these birds eat seeds of this size.
Encephalurtos lzildehrundtii A. Braun & Boucht
Encephalartos hildebrandtii A. Braun & Bouchi, Index Seminum in horto
botanic0 Regnum Berolinensi collectorum, 18 (1874) Encephulurtos lzilclebrandtii var. hildebrandtii.
Typus. Hildebrandt (B. holo, I. iso.)
Description amended from Melville (1957). Trunk to 3 m high and 340 mm
diameter. Leaves linear, oblanceolate, 2-3 m long, 300-550 mm wide,
tapering to the rounded apex and gradually to the base, rachis clearly
grooved above, between the leaflets, swollen petiole base at first fulvous,
woolly-tomentose, exposed parts glabrous at maturity. Median leaflets
linear lanceolate, pungent, 200-260 mm long 28-36 mm wide, apex acuminate, bare, or with 5-7 spiny teeth, nearly straight below, arching above;
margin with 2-7 spreading spiny teeth on each side, often crowded near the
base, coriaceous, glossy dark green above, paler below and obscurely striate
with 25-36 parallel nerves; lower leaflets palmate, spiny, passing to
trifurcate; bifurcate and simple spines extending to the swollen petiole base.
I have modified the dimensions given by Melville (1957) on the basis of my
observations of specimens growing in a colony near Gedi (3”45’S, 39”05’E)
about 20 km west of Malindi on the Kenya central plain as in my opinion these
plants represent a true population of the species. I have not seen the type
material in England but from my field observations I am convinced that the
plants growing on the East-African coastal plain comprise a different species
from those found in Western Uganda and described below as E. lawentianus De
Wild. Soil tests at Gedi show 65% sand, 17% silt and 21% clay with a pH of 6.0.
There were clear deficiencies in nitrogen, potassium and phosphorus.
Encephalurtos hildebrandtii var. dentatus Melville, Kew Bulletin ; 248
(1957).
Typus. Wigg 1044, Dar-es-Salaam, cult (K. Holo.).
Previously only known from the six specimens growing in the old Arab
cemetery about 1 5 km south of Dar-es-Salaam. A new colony has now been
20
282
D. HEENAN
discovered (0"25'N, 33'23'E) about 20 km east of Jinja in Uganda and 5 km
east of the ruined Fort Thuston (alt. 1200 m). The colony is growing in
rocky outcrops and is adjacent to an old Arab village which is reported to
have been wiped out towards the end of the last century by sleeping
sickness. This may account for the presence of the specimens in the Moslem
cemetery near Dar-es-Salaam. A further colony was reported but neither
locality nor specimens were seen. I t lies approximately 5 km south-west of
the old village.
Encephalartos laurentianus De Wild.
Encephalartos laurentianus De Wild., Annales dzr Musie d u Congo Relge
Jiries de botaniyue, Bruxelles 5: 10 (1903).
Typus. Oentil 9 8 , August 1902 (Br. 13010.) Belgian Congo (Zaire), Kasongo,
Kwango River.
The specific identity of plants from the Mpanga River Falls (0"05'N, 30"
20'E) is confused. They have been described by Prain (1917), Eggeling (1940)
and Robyns (1947) as h'. laurentianus; Melville (1957) included them in E.
hildebrandtii. I believe Melville wrote such a broad description of E.
Izildebrundtii to cover both the specimens from the East African coast (Kenya,
Tanzania) and the Tor0 District of Uganda. I have accordingly amended the
first part of his description of E. lzildebrandtii on the basis of my field
observations.
The Mpanga River Falls specimens are intermediate in vegetative features
between E Izildebrandtii and E. laurentianus, as noted by Melville, and shown
in Table 1.
Observations of the cones (Table 1 ) again suggest a closer resemblance t o E.
la u ren tian us.
I believe the above facts are sufficient to place these plants in E. lazirentianus
De Wild. though their status as a subspecies of E. laurentianus is not ruled out.
The phytogeography of the Rift Valley does not seem to be significant because
the Mpanga River, emptying into Lake Idi Amin (formerly Lake George) is
between the arms of the Rift. The eastern Zaire species occurs near Irumu
(approximately 1"40'N, 29" 45'E-the exact localities of the colonies have not
been observed or recorded) on the western side of the Rift. It is reported that
Encephalavtos also occurs on the Western Puwenzoris, and if located, these
populations may confirm the present assumption that the Mpanga River
specimens are of E. laurentianus.
En cep halartos tegulaneus Melville
Most colonies are high in mountainous terrain and usually of very difficult
access, the type locality being on Mount Lololokwe in the Matthews Range in
Kenya. It was noted that this species grows much taller than the 7 m Melville
(1957) records. Trunks up t o 10 m were recorded in this area.
It is interesting to note that a number of large recumbent specimens were
found. These had been partially hollowed out lengthwise by the local Samburu
herdsmen t o form cattle drinking troughs and the plants were still living.
28 3
CYCADS O F CENTRAL AFRICA
Table 1. Comparisons of published and observed dimensions of Enceplzalartos
lzildebrandtii and E. lauren tianus
E. h ilde brandtii
(after Melville, 1957)
At Gcdi
A t Mpanga River
E. laurentianus
(after Melville, 1957)
Trunk
Height:
Diameter:
up t o 6 m ( ? )
up t o 0.3 m
up tn 2.5 m
up to 0.35 m
rarely sessile
over 3 m
up to 0.8 m often
sessile
up t o 15 m
up to 1.25 m often
sessile
Leaves
Length:
Width:
2-3 m
300-650 mm
2-3 m
400-550 mm
over 3 m
up to 650 mm
4-6 m
500-900 mm
Rachis
slightly grooved
clearly grooved slightly grooved
n o t grooved
Leaflets
New leaves
Veins:
Length;
Width:
26-40
150-350 mm
13(?)-45 mm
fulvous
25-36
200-260 mm
28-36 mm
mcd. green
32-34
300-330 mm
30-34 mm
45-65
350-500 mm
40-70 mm
Spines
Above:
Below:
4-9
1-5
5-7
2-4
5-8
2-5
9-1 5
9-1 5
Male cones
Length:
Diameter:
Peduncle:
200-500 mm
50-90 mm
50-250 mm
n o t observed
up t o 360 mm
60-80 mm
u p t o 350 mm
170-350 mm
60-100 mm
250-300 mm
Female cones
Length:
Diameter:
Peduncle:
280-600 mm
150-250 mm
40-60 mm
n o t observed
up to 1 5 0 mm
up t o 170 mm
up t n 120 mm
350-450 mm
up t o 200 mm
short (?)
Colour
pale yellow
pale green becoming
brownish orange
reddish
~.
-
Encephalartos poggei Ascherson
This species (local name: 'Kabwe A Katende') was originally described from
between the Luisa and Casserigi Rivers in Zaire. Three colonies were
investigated S.E. of Kananga (previously Luluabourg) in Zaire:
1. Approximately 70 km S.E. of Kananga on the road to Luisa (6" 35'S,
22" 10'E).
2. On the road close to ChQtes de Katende (6" 30'S, 22" 20'E).
3. Near the main road approximately 5 km S.E. of Mweru Ditu (7"00'S,
23" 30'E).
Other colonies were reported but not investigated.
It was noted that in all colonies visited the caudex of some specimens grew
much taller than the 1 m previously described, up to 2 m being recorded.
En ceph alar t 0s b u balin us M elville
Type localitv (2"11'S, 35'40'E) about 2 0 km west of Lake Natron, Masai
District, Tanzania. In the type area a number of trunks were observed to a
length of 2 m recumbent and 4 5 cm in diameter, considerably larger than
originally described (Melville, 1957).
284
D. HEENAN
Encephalartos gratiis Prain
Further colonies (type locality, Mount Mlanje, Malawi) of this species were
found in the Namuli Mountains of Mozambique, N.E. of Vila Junqueiro and
S.W.of Nampula (15"25'S, 37"05'E). Trunks of up to 2.2 m in height were
recorded and diameters of 0.6 m were not uncommon. Female cones in all
cases have a set of apical leaves, usually about six. These are miniatures of the
main leaves but in the case of the Namuli specimens these grow to a length of
just over 1 m whereas those at Mlanje averaged 100-200 mm. I t appears that
most of the Namuli plants are being eradicated in the wild to make room for
new tea estates. A form of E. gratus has been reported from near Mavita
(19' 30'S, 32'05'E) about 75 km S.W.of Vila Pery. The leaflets do not bear as
many prickles as the Northern varieties and are more uniform in breadth. These
are now under observation and, when further material has been investigated,
may be worthy of subspecific rank. They appear to be intermediate between
this species and the next.
Encephalartos manikensis Gilliland
The type locality is on Mount Gorongowe in the Stapleford Forest Reserve,
Rhodesia. The area covered by this species appears to be far larger than
reported by Dyer & Verdoorn (1969), specimens having been located 1 5 km
east of Birchenough Bridge (19"55'S, 32"30'E) 30 km west of Goonda
(19"45'S, 33'45'E); in the N.E. as far as Aaopeia (17"58'S, 35'35'E) on the
northern side of the Zambezi River; and in the N.W.in the vicinity of Mt
Darwin (16"45'S, 31" 35'E). It is probable that this is not the full range, with
unconfirmed reports of this species in the N.W.near to Cabora Bassa (15" 35'S,
32"30'E). Quoting Dyer & Verdoorn (1969) "There are for instance some
plants from near Bandula and Caruso in Mozambique, here 'clumped' with E.
manikensis, which the late H. B. Christian regarded as distinct. Localities which
should certainly bring their reward if thoroughly surveyed are: Mt Chinyazange, the top of Mt Nhaungwe and the hill of Chigamba which lie north and
south of Bandula".
From observations of specimens under cultivation from all these areas,
differences are so slight as to be negligible with the exception of the M t
Chinyazange locality. Dyer (1972) shows a photograph on page 216 (fig. 12) of
Encephalartos sp. (E. "chinhazany") but there is no reference to this in the
text! Obviously extensive study is still necessary but will only be possible with
cultivated specimens for some time to come due t o the political problems in
the country of their natural habitat.
Of the species subdivided from E. manikensis by Dyer & Verdoorn (1969), a
probable form of E. chirnanimaniensis was found growing near Chipinga
(20" 15'S, 32'40'E). Again further investigation appears necessary. Also E.
pteroganus has been recorded from a place named Chimoio whereas it
previously was considered restricted to the type locality, M t Mruwere.
285
CYCADS O F CENTRAL AFKICA
lmperfectlj~known species o f Encephalartos
Enccphalartos sp. ‘A’ Fig. 1 B
This was first reported by Turrill & Milne-Redhead ( 1 9 5 8 ) . In addition t o
their description the following points were noticed on two plants under
cultivation (Heenan E 1 3 0 , Heenan E213) which were collected from the type
locality :
(a) The rachis has two grooves coinciding with the basal attachments of the
leaflets.
(b) The rachis is puberulent throughout its entire length but more so on the
underside.
(c) The leaflets were not noticeably widely spaced. On the contrary, under
cultivation, they were almost overlapping with a half-opened venetianblind effect.
(d) Leaflets were for the most part entire with occasional (1-2) very small
spiny teeth on the upper margin. No spines were observed on the lower
margin.
It is interesting to note that a few specimens discovered near Nampula
( 1 5 ” lo’s, 39”15’E), Mozambique by Mr Ian Turner bear a close resemblance
to this species.
Ericeplialartos sp. ‘B’ (‘Voi’) Fig. 1 C
Trunk up t o 2.2 m high, 0.35-0.6 m diameter, with a tendency t o taper
towards the top. Leaf scars very irregular in size and shape varying from
A
0
5
10
crn
Figure 1. Median leaflets of Encephalartos species. A, E. Zuurentianus from the Mpanga River.
Uganda; B, Encephalartos sp. ‘A’ from Usumbra Mountains, Tanzania; C, Encephalartos sp. ‘B‘
from Voi, Kenya.
286
D. HEENAN
30’
Figure 2. This shows the sighted and reported localities of Encephalavtos sp. ‘C’ in the Mpanda
district of Western Tanzania (East Africa). Localities investigated: 1 , Wanzizi hills, 1 5 0 0 m ; 2,
Kabulwanyele, 1200 m; 3 , Mt Karobna, 1 8 0 0 m. Localities not investigated, known only from
previous reports: 4, Mt. Sitebi, 1950 m ; 5, Lugala Hills 1 5 0 0 m ; known from reports of locals:
6 , Ikate; 7, Manyika.
horizontally distended triangles 30 by 60 mm to parallelograms 60 by 80 mm.
The most noticeable feature of this species is the unusually swollen base of the
rachis with the subsequent distinctive leaf scars on the caudex. Leaves mainly
oblong, rounded at apex and narrowing gradually t o the base, up t o 3.7 m long
b y 0 . 6 5 m wide. Leaflets linear lanceolate, pungent, coriaceous,
250-350 mm long by 30-40 mm wide, overlapping and mainly subopposite,
becoming trifurcate, bifurcate and finally with up to 1 5 pairs of spines
terminating about 80 mm from the base of the greatly swollen rachis,
which is not gooved. Median leaflets usually with 4-6 distinct spines on
the upper margin, usually with 3-4 of these spines close to the basal
attachment; lower margin entire, sometimes with up to two smaller spines;
under-surface clearly striate with 3 0-45 parallel nerves.
CYCAD5 O F CENTRAL AFRICA
287
These species occur approximately 25 km S.E. of Voi (3”40‘S, 38”45’E),
Kenya in the Maunga Mountains at an altitude of about 1000 m The colonies
are to be found on Mlilonyi, Nyangala, Sagala and Kasigau growing in partial
shade and in open country. I t is worth noting that all specimens growing in the
open reached only two-thirds the size of those in partial shade with regard to
both trunk and leaf development, probably indicative of the more favourable
humid conditions under the forest canopy.
Encephalartos sp. ‘C’ (“Mpanda”)
Reports had been received from the famous lepidopterist, Kielland, of
Encephalartos growing in S.W. Tanzania mainly in the Mpanda district, The
map (Fig. 2) shows the area in detail and the reported sightings. A total of
almost five weeks, split into two visits, was spent in this district. Conditions were
the worst encountered with roads and bridges totally washed away, grasses up
t o 3 m making visibility almost impossible; normally dry areas were waterlogged and, as a result, mosquitoes and tsetse flies were in their glory. In the
end one specimen was found and collected but not all the areas were
investigated and even those visited should be thoroughly searched again in
better conditions. This particular plant appears t o have been connected with
ritual practices by the local witchdoctor who also maintained that he had
knowledge of other localities. It took great powers of persuasion t o induce him
t o part with this one specimen and t o date it has not produced either leaves or
cones. Some material from this area is held at the herbarium in Nairobi and Mr
D. S. Heenan believes that it appears t o show a close affinity to E. poggei As
permission could not be obtained from the government of Zaire t o travel to the
Muhila Plateau-E. marzinguensis Devered (19 59)-nor t o the Kundelunga
Plateau-E. schmitzii Malaisse (1969)-due to internal security problems at the
time, it was impossible t o collect herbarium material or specimens for later
comparison and study. These could have shed some light on the ‘Mpanda’
species.
CONCLUSIONS
Within the .last seven years, seven new species of Encephalartos have been
described. From the information gathered on these expeditions plus reports of
a new species in Nigeria it will be seen that much more field work remains to be
done. The difficulties of travel, especially to the more remote parts of Africa,
appear to be increasing rather than improving, and it will be more than ever left
t o expeditions by the younger, intrepid explorer-botanists.
ACKNOWLEDGEMENTS
My thanks go to the people who made these expeditions possible, the
governments of the countries visited who helped to smooth the way, all
who put in the right word or supplied the right piece of paDer at the
right time, especially Mr J. Coldwells, Mr P. Bally, Dr J. Gillett; and Mr
A. Stuart-Smith: t o Mr A. B. Katende, Mr D. Stallard, and Mr A. Graham,
who accompanied my son, Mr D. S. Heenan, on one or other of the
expeditions. Financial assistance is acknowledged from Professor A. Verga,
the late Professor L. Califano, Mr B. Greenberg, Mr R. Rapp, Mr W.
Sumawong, Mr J. A. Smit and Mrs Ponellis.
288
D. €IEENAN
R El:ERENCFS
DEVRED, R., 1959. Une Cycadacke nouvelle d u Congo Belge: Encephalavtos marunguensis Devered
Bulletin du Society Royal, Botanique du Belge, 91: 103-108.
DVER, K.A., 1972. Cycads. Cactus and Succulent Journal (U.S.), 44: 209-216.
DYER, R. A. & VERDOORN, I. C., 1969. Encephalartos manitensis and its near allies. Kirkia, 7:
147-1 58.
EGGERLINC;, W. J., 1940. The indigenous trees of Uganda Protectorate. Entebbe.
HALL, J. B. & JLtNIK, J., 1967. Observations on West African Cycads in Ghana. Nigerian Field, 32:
75-81.
LISOWIKI, S. & MALAISSE, F., 1971. Encephalartos mavunguensis Devered; Cycadacke endkmique du
plateau des Muhila (Katanga, Congo-Kinshasa). Bulletin du Jardin Botanique national de Belgique,
40: 357-361.
MALAISSE, F., 1969. Encephalartos schmitzii Malaise; CycadacPc nouvelle du Congo-Kinshasa, Bulletin
d u Jardin Botanique national de Belgique, 39: 401.406.
MELVILLE, R., 1957. Encephalartos in Ccntral Africa. Kew Bulletin, 12: 237-257
PRAIN, D., 1917. In Oliver et al. (Eds), Flova du Congo Belge e t du Kuanda-Burundi, 1 : 1-4. Bruxelles.
KOBYNS, W . , 1947. Flova des spermatophytes du Parc National Albert, 1: 1-4. Bruxelles Institut
des Parcs Nationaux du Congo Belge.
TURRILL, W. R. & MILNE-REDHEAD, E., 1958. Flora of Tropical East Africa, I : 1-10, London.