Content uploaded by Johan L.C.H. van Valkenburg
Author content
All content in this area was uploaded by Johan L.C.H. van Valkenburg
Content may be subject to copyright.
A revision of the genus Sclerosperma (Arecaceae)
J. L. C. H. van Valkenburg
1,2
, T. C. H. Sunderland
3
& T. L. P. Couvreur
1
Summary. A taxonomic revision of the palm genus Sclerosperma (Arecaceae) is presented. Three species are recog-
nised: S. mannii H. Wendl., which is relatively widespread from Liberia to the Democratic Republic of Congo; S.
walkeri A. Chev., which is apparently confined to the interior of Gabon and a band along the Congo River; and S.
profiziana, a new species previously considered conspecifictoS. mannii that is found in southwest Ghana, Congo,
the Democratic Republic of Congo and Angola. The taxonomic history, morphology, distribution and conserva-
tion status of the genus and each species are discussed.
Key Words. Africa, Arecaceae, evergreen rainforest, Lower Guinea, Sclerosperma.
Introduction
The first two authors of this paper first met in Rome in
2001 at a FAO workshop on prospects for the conser-
vation and sustai nable development of the rattan
resource (Dransfield et al. 2002). One of us was then
working in South-East Asia (Van Valkenburg 1997), the
other in West and Central Africa (Sunderland 2000).
In 2002, we became neighbours when the first author
was appointed head of the Herbier National du Gabon
in Libreville, Gabon; the second author was still
working at Limbe, Cameroon. We decided to join
forces and focus on the poorly collected rattans of
Gabon. During joint palm hunting trips, neither of us
initially paid much attention to either Podococcus or
Sclerosperma. It was only when the first author was
working on the Arecaceae account for the ‘Checklist of
Gabon’ (Van Valkenburg 2006) that he stumbled upon
some obscure names. We decided to have a closer look
at Podococcus and Sclerosperma. Two more fieldtrips to
Gabon confirmed our ideas with respect to these
names, and resulted in some fine collections of some
long-forgotten species (Van Valkenburg et al. 2007).
Taxonomic History
The genus Sclerosperma was first described in 1864 by
Gustav Mann and Hermann Wendland on the basis of
material belonging to S. mannii H. Wendl. collected by
Mann in inundated forest near the Gaboon (now the
Ogooué) River from Point Clara upwards. Another
palm species of the forest understorey, Podococcus
barteri G. Mann & H. Wendl., also from Gabon, was
described in the same paper, and the two taxa were
presented in a fine illustration of African palms in
Tabula 38 . It was not until the 193 0s that two
additional species of Sclerosperma were described: S.
dubium Becc. from Equatorial Guinea was described
from a single carpological collection (Martelli 1934)
and S. walkeri A. Chev. from Gabon was described
from an infructescence and a juvenile leaf (Chevalier
1931). However, both species have remained some-
what enigmatic ever sin ce. Sclerosperma dubium
remained known from the type collections only, and
aside from the type specimen in Paris, just one
additional collection had been labelled as S. walkeri.
With new collections that arrived from West Africa,
the circumscription of S. mannii in the second edition
of the ‘Flora of West Tropical Africa’ (Russell 1968)was
widened to include collections that have conspicuous
undivided leaves originating from southwest Ghana.
In the Congo, a species of Sclerosperma with
undivided leaves, known by its vernacular name
‘mabondo’, an appellation used by the inhabitants of
the Kisantu region of the Democratic Republic of
Congo (Profizi pers. comm.), was listed as S. mabondo
De Wild. by Renier (1948). This name has been used
in connection with the plants from the Congo Basin
but appears to have never been validly published (Tuley
Accepted for publication October 2007.
1
Nationaal Herbarium Nederland, Wageningen Branch (Herbarium Vadense), Biosystematics Group, Wageningen University, Generaal Foulkesweg 37,
6703 BL, Wageningen, The Netherlands.
2
Present address: Plant Protection Service , P.O. Box 9102, 6700 HC, Wageningen, The Netherlands.
3
Forests and Livelihoods Programme, Centre for International Forestry Research (CIFOR), P.O. Box 6596 JKPWB, Jakarta 16680, Indonesia.
KEW BULLETIN VOL. 63: 75– 86 (2008)
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
1995). Jean-Pierre Profizi, who has undertaken detailed
fieldwork in Congo (Brazzaville) as well as partial
herbarium studies of the genus, recognised the name
to be invalid and attempted to remedy the situation by
preparing a manuscript naming it S. gilletii. Unfortu-
nately, S. gilletii was also never validly published.
TheissueofthetaxonomicstatusofScler osperma with
entire, undivided leaves in Ghana was also raised by
Moore (1971) af ter his visit to both Ghana and Gabon.
Consultation by the first author of the extensive
herbarium collection of Sclerosperma material from
Congo at Meise suggested that this material wi th
undivided leaves deserved a distinct taxonomic status,
supporting the conclusions of both Moore and Profizi.
This was further supported by the examination of
material from the Bailey Hortorium and Kew Herbarium
and by the recent arrival of new collections from Ghana.
Although elaborately discussed by Raponda-Walker &
Sillans (1961), Sclerosperma walkeri is merely mentioned as
a species of doubtful status in the checklist of vascular
plantsofGabon(VanValkenburg2006). However, a
closer look at the protologue and examination o f the
type specimen from Paris, and the arrival of further new
collections from Gabon, confirmed the status of S.
walkeri (Van Valkenburg et al. 2007). A similar situation
exists for Podococcus acaulis Hua, another understorey
palm found in Gabon that was described and then
subsequently relegated to synonymy based on an
incomplete understanding of the genus (Van Valkenburg
et al. 2007; Van Valkenbur g & Sunderland 2008).
The molecular phylogeny based on three chloroplast
markers by Asmussen et al. (2006)placedSclerosperma in
the Arecoideae sub-family, but with no other well -
supported relationships to other genera. The position
of Sclerosperma has to be determined, and the sister
genus of Scleropserma still has to be determined.
At the generic level, recent phylogenetic studies have
corroborated the unique morphological and palynolog-
ical characters of Scler osperma andplacedthegenusina
tribe of its own, Sclerospermeae (Dransfield et al. 2005).
Morphology
Habit
All species of Sclerosperma are small clustering under-
storey palms, 2 – 6(– 12) m tall. They are unarmed,
pleonanthic, monoecious palms that grow in tropical
lowland rainforest, in swampy sites and, less common-
ly, on terra firma.
Stem
The stem in Sclerosperma is virtually absent and
persisting underground, stout and possessing closely
ringed leaf scars or extending horizontally and
producing suckers, rarely producing a stem of 9 cm
diameter and up to 2 m height in S. profiziana.
Leaves
The crown consists of numerous leaves, broadly
radiating, pointing upwards, that accumulate debris,
thereby obscuring the base of the plant. The leaves are
reduplicate, undivided or irregularly pinnate, the apex
deeply bifid with the rachis continued in a fibre. The
petiole is long and slender, and the rachis bears a
prominent ridge adaxially. The upper surface of the
blade is dark green, whereas the unde rsurface is
glaucous to silvery and with small scales along the veins.
Inflorescences
All Sclerosperma species have intrafoliar, solitary, spicate
inflorescences, which are protogynous. The inflores-
cence is enclosed by a peduncular bract that becomes
web-like in the median part at anthesis and that has a
distal opening. This peduncular bract is somewhat
persistent but generally disintegrates when fruits are fully
developed. During anthesis of the female flowers, the
inflorescence is reported to have an elevated tempera-
ture and to be filled with a transparent liquid at the base
(Profizi, pers. comm.). Numerous Nitidulae beetles visit
the inflorescenceatthattime(Profizi, pers. comm.).
Flowers
The flowers are arranged in triads of two distal
staminate and a proximal pistillate flower basally, or
staminate flowers in the upper part of the rachis.
Pollen
Pollen grains of Sclerosperma are reported to be single,
triangular, and heteropolar with a triporate, subapical
and circular aperture, and to have an average
diameter of (37 –) 45.7(– 59) μm (Uhl & Dransfield
1987; Harley 1999; Harley & Dransfield 2003).
Fruits and Seeds
The infructescences are often obscured by accumulated
debris. The fruits are 1-seeded, globose and generally
depressed apically aroundashortbeakofstigmatic
remains. They are dry; purplish to black at maturity. The
seeds are globose and somewhat rough, with an elongat-
ed hilum, homogenous endosperm and basal embryo.
Germination is remote-tubular with a bifideophyll.
Distribution and Ecology
The genus Sclerosperma occurs from western Liberia to
the tributary of the Congo River, as far east the border
region with Rwanda and southeast into Kasai Orien-
tale in the Democratic Republic of Congo. The
distribution in West Africa appears to be rather
disjunct with populations in Liberia, southwest Ghana
and on both sides of the Nigeria–Cameroon border.
Sclerosperma mannii is reported as being present on
Bioko (Guinea López 1946;Aedoet al. 1 999),
although no specimens are cited from this island.
76 KEW BULLETIN VOL. 63(1)
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
Sclerosperma is present in lowland evergreen forest (from
sea level to 1,400 m) in swampy areas, in periodically
flooded forest , in valley bottoms, and along streams and
on riverbanks, but it also occurs on terra firma including
low hills. The genus is present in old secondary forest
dominated by okoumé (Aucoumea klaineana)andpersists
in secondary growth near human habitations, where its
leaves are often collected for roof thatching. Prelimi-
nary conservation status assessments are provided
following IUCN guidelines (IUCN 2001).
Taxonomic Treatment
Sclerosperma G. Mann & H. Wendl. (1864: 427);
Wright (1902: 100); Renier (1948: 83); Tomlinson
(1962: 103); Russell (1968: 161); Moore (1971: 111);
Uhl & Dransfield (1987: 474); Tuley (19 95:93);
Dransfield & Uhl (1998: 376). Type species Sclero-
sperma mannii H. Wendl.
Short or acaulescent, clustering, unarmed, pleonanthic,
monoecious palms. Stem,ifevident,creepingorerect,
rather stout, closely ringed with leaf scars. Leaves
undivided or irregularly pinnate, deeply bifid in juveniles,
ascending; sheath rather short, splitting opposite the
petiole, mar gins fibrous; petiole long, slender adaxially
channelled, abaxially rounded; leaflets, when present,
alternate to subopposite, of several narrow folds, midribs
prominent, marginal ribs next largest, plication redupli-
cate, blade adaxially dark green, abaxially glaucous to
silvery and with small scales along the veins, folds apically
praemorse, margins minutely toothed, transverse veinlets
not evident. Inflorescence interfoliar , concealed among the
leaf bases and sometimes partially obscured by accumu-
lated debris, spicate; peduncle very short, elliptic in cross-
section, densely tomentose; prophyll strongly 2-keeled,
becoming fibrous; peduncular bract longer than the
prophyll, tubular , forming a fibrous net around the
flowers, apparently opening distally and inflorescence
becoming partially exserted, two incomplete, pointed
peduncular bracts born laterally just below the flowers;
rachis longer than the peduncle, but short, bearing a few
triads of flowersatthebaseandnumerousrowsof
staminate flowers distally, triads each subtended by a
shallow pointed fibrous bract, the distal staminate flowers
by small acute bracts; floral bracteoles present in triads,
flat, ± rounded and partially united. Staminate flowers in
triads ± pedicellate and asymmetrical, distal flowers
sessile, symmetrical; sepals 3, distinct, imbricate basally,
elongate, tapering, truncate apically or wit h a short
central point; petals 3, distinct, valvate but tips flattened
and buds truncate apically, thick. Stamens 60 – 100,
filaments very short, ± triangular, anthers elongate,
basifixed, connective prominent, apiculate; dehiscence
latrorse; pollen ± triangular, triporate, with reticulate,
tectate exine; pistillode lacking. Pistillate flowers larger than
the staminate, broadly ovoid; sepals 3, connate in a three-
lobed, glabrous cupule or margins of two sepals distinct
and imbricate, somewhat angled by mutual pressure;
petals 3, distinct, asymmetrical, broadly imbricate with
thick valvate tips; staminodes 6 (according to Uhl &
Dransfi
eld 1987), very small, triangular; gynoecium ovoid,
unilocular, uniovulate, covered in thin brown scales,
bearing a large, cap-like, 3-angled stigma; ovule ±
pendulous, probably campylotropous. Fruit globose to
obovoid depressed apically around a short beak of
stigmatic remains, purplish to black at maturity; exocarp
thin, mesocarp thin, parenchymatous with silica inclu-
sions, endocarp bony, thick, irregularly and shallowly
pitted externally, with basal pore region. Seed globose to
obovoid, somewhat rough, hilum elongate, endosperm
homogenous; embryo basal. Germination remote-tubular;
eophyll bifid.
Key to the species of Sclerosperma
1a. Short or acaulescent, clustering palm to 6 (–12 m) tall, leaves undivided, petiole 60 – 100(– 400) cm long,
rachis 150 – 200(– 400) cm long; blade elongate-cuneate in outline 20 – 60(– 140) cm at its largest width
............................................................................................................................................................... 2. S. profiziana
1b. Short or acaulescent, clustering palm to 5 m tall, leaves irregularly pinnate, petiole (60 –)150 – 300(– 400) cm
long, rachis (80 – )150(– 200) cm long; blade elongate-cuneate in outline ....................................................... 2
2a. Leaflets 8 –17(– 24), of several narrow folds (3 –)6 – 9(– 13) cm wide; rachis of infructescence 3 – 6 cm long,
bearing up to 17 fruits, but in generally fewer; fruits 2.5 – 3(– 3.5) cm long, 2.2 – 2.9 cm in
diameter..................................................................................................................................................... 1. S. mannii
2b. Leaflets (20 –)25 – 40, of several narrow folds 1.2 – 6 cm wide; rachis of infructescence 6 – 11 cm long, bearing
up to 30 fruits; fruits 4 – 5 cm long, 3 – 3.5 cm in diameter......... ...................................................... 3. S. walkeri
1. Sclerosperma mannii H. Wendl.inMann&
Wendland (1864: 427); Kerchove de Denterghem
(1878: 35); Drude (1895: 136); Hua (1895: 315);
Wright (1902: 101); De Wildeman (1928: 309); Pelle-
grin (1938: 56); Guinea López (1946: 246); Renier
(1948: 83); Descoings (1961: 47); Russell (
1968: 161);
Moore (1971: 116) as Sclerosperma with dissected leaves;
Letouzey (1978: 306); Tuley (1995:93);Aedoet al.
A REVISION OF THE GENUS SCLEROSPERMA (ARECACEAE) 77
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
(1999:377);Govaerts&Dransfield (2005:203);
Valkenburg (2006: 321). Type: Gabon, Estuaire, Cap
Santa Clara, 1861, G. Mann 1046 (holotype K!).
Sclerosperma dubium Becc. in Martelli (1934); Tuley
(1995: 97); Govaerts & Dransfield (2005: 203);
synon. nov. Type: Equatorial Guinea, Rio Muni,
Ntüm Gebiet 1910, Wölfert s.n. (lectotype HBG!,
isolectotype WAG!, designated here); Equatorial
Guinea, Rio Muni, Ntüm Gebiet, 1910, Wölfert s.n.
(paralectotype HBG!, designated here).
Short or acaulescent, clustering palm. Stem, if evident,
very short, rather stout, closely ringed with leaf scars.
Leaves divided, very large, deeply bifid in juveniles,
ascending; sheath to 35 cm, splitting opposite the
petiole, margins fibrous; petiole slender, 150 – 300 cm
long, adaxially channelled, abaxially rounded proxi-
mally, becoming triangular distally; rachis 80 – 150 cm
long, continuing in the terminal leaflet, abaxially
rounded, adaxially with a prominent ridge, leaflets
8 –17(– 24), sub-opposite to alternate, folds 30 – 45
(– 63) (3 –)6 – 9(–13) cm, the upper leaflet deeply
bifid, broadly rhomboid in outline, base of the upper
leaflet asymmetrical, 30 – 45 (20 –)30 – 45 cm,
midribsprominent,marginalribsnextlargest,blade
adaxially dark green, abaxially glaucous to silvery and
with small scales along the veins, folds apically prae-
morse, margins minutely toothed, transverse veinlets not
evident. Inflorescence solitary, interfoliar, concealed
among the leaf bases and often partially obscured by
accumulated debris; peduncle to 12 (– 19 cm) long,
elliptic in cross-section to 1.5 cm wide, densely tomen-
tose; prophyll occasionally to 20 cm long; peduncular
bract 18 –
25 cm long; rachis 10 – 14 cm long. Staminate
flowers sepals 3, distinct 3 – 4 mm long; petals 3, distinct
6 – 8 mm long, elliptical; stamens c. 60, filaments very
short, ±triangular; pistillode lacking. Pistillate flowers
larger than the staminate, broadly ovoid; sepals 3,
connate in a 3-lobed, glabrous cupule or margins of 2
sepals distinct and imbricate, somewhat angled by
mutual pressure; petals 3, distinct, asymmetrical. Rachis
of infructescence 3 – 6cmlong,bearingupto17fruits,
but generally fewer. Fruit 2.5 – 3(– 3.5) 2.2 – 2.9 cm.
Seed globose, 1.5 – 2.3(– 2.5) 2 – 2.5 cm (Fig. 1A – E).
DISTRIBUTION. Sclerosperma mannii appears to have a
rather disjunct distribution with a population in
Liberia and fr om southeast Nigeria southward to
Congo and as far east as the border area of Congo
and Rwanda. The species was reported to be present
on the island of Bioko by Guinea López (1946)
quoting Gómez Moreno , but without a specimen
citation (no specimens to corroborate its presence
on this island have been received from MA). Map 1.
LIBERIA. Lower Margibi, along the Monrovia-Careys-
burg highway on your right, Zewald junction: LRC
factory, Karfier Clan, Zeor village, 50 m, 15 Dec. 2005,
D. Kwewon 2005/1 (WAG!); 1904, M. J. Dinklage s.n.
(HBG!).
NIGERIA. Cross River State, between mile 13 – 14
along Eket to Oron road, 330 m, 12 Sept. 1972,
Otedoh, M.O. 7265 (K!); Ikot Opora, 2 Jan. 1965, P.
Tuley s.n. (K!); Ojo road, 120 m, 4 May 1964, P. Tuley
604 (K!); Ojo Road, near Ikot Okpora, 14 July 1963, P.
Tuley 654 (K!); Oban, S. Nigeria, 1911, P. A. Talbot 737
(BM!).
CAMEROON. Central Province, 1 km SW of Ngoumou,
19 Feb. 1977, J. Lowe 3167 (K!); about 6 km along the
road from Ngoulemakong direction N, village Obégué
is 2 km W of the road, about 1 km S of this village,
720 m, 26 Dec. 1997, X. M. van der Burgt 312 a
(WAG!); South Province, Djoum to Sangmelima road
at Alouma, 9 Sept. 1999, T. C. H. Sunderland 1863
(BR!, K!, MO!); South-West Province, South Korup
Reserve, bank of Mana River, Map # NB 32 IV Buea-
Douala, 50 m, 6 July 1983, D. W. Thomas 2247 (MO!);
Korup National Park, 50 m, 5 Dec. 1984, D. W. Thomas
4143 (MO!); 15 miles W of Mamfe on Ikom road,
Kembong F. R., 20 March 1957, P. B. Tomlinson 57/1
(BH!); Kembong forest reserve: near junction of
Oban-Mamfe and Ikom-Mamfe roads , 16 March
1955, P. W. Richards 5215 (K!); Korup National Park,
P plot, subplot 26A, 100 m, 3 Dec. 2005, X. M. van der
Burgt 811 (SCA, WAG!, YA).
EQUATORIAL GUINEA. Rio Muni, Spanish Guinea, Ntüm
Gebiet, 1910, W. Wölfert s.n. (HBG!, WAG!); 1910, W.
Wölfert s.n. (HBG!); 1910, W. Wölfert s.n. (HBG!); Rio
Muni, Litoral, Bata-Mbini Road, 17 km from Bata, 13
March 1997, T. C. H. Sunderland 1794 (K!, WAG!);
Ndote Forest Reserve, 13 Sept. 1999, T. C. H. Sunder-
land 1868 (K!, WAG!).
GABON. Estuaire, in swampy places near the River
Gaboon, from Point Clara upwards, 1 m, 1861, G.
Mann 1046 (K!); about 89 km from Libreville on road
to Mela, Nka’n, and Medouneu, 10 March 1971, H. E.
Moore Jr. 9899 (BH!); Forêt de Mondah, sentier des
conservateurs, 80 m, 27 April 2005, J. L. C. H. van
Valkenburg 3235 (BR!, LBV!, WAG!); forest in man-
grove, c. 17 km NE of Libreville, 5 m, 9 Aug. 1985, J.
M. Reitsma 1306 (NY); Ngounié, road Fougamou to
Lambarene near village Kesi, 90 m, 25 April 2005, J. L.
C. H. van Valkenburg 3234 (BR!, LBV!, WAG!); Nyanga,
Mayombe, sur la route de Massanga à Moabinako, 21
Oct. 1908, G. M. P. C. Le Testu 1428 (BM!, P); chantier
SFN, 60 m, 2 Dec. 2003, J. L. C. H. van Valkenburg 2682
(K, LBV!, MO, P, SCA, WAG!); Ogooué-Maritime,
former extraction road system accessible from Peni
CBG chantier, 250 m, 24 April 2005, J. L. C. H. van
Valkenburg 3230 (BR!, LBV!, WAG!).
ANGOLA. Cabinda, Mayumbe, Portuguese Congo,
BucoZauMaiombe,Jan.1917,J. Gossweiler s.n.
(BM!); Portuguese Maiombe: Chiluango, 1919, J.
Gossweiler s.n. (K!); Mayumbe, Portuguese Congo,
78 KEW BULLETIN VOL. 63(1)
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
Fig. 1. A – E Sclerosperma mannii. A habit; B leaf; C infructescence; D fruit; E remnant of infructescence; F – L Sclerosperma walkeri. F habit; G
leaf; H infructescence; J fruit; K fruit in cross-section; L remnant of infructescence. A from photo Valkenburg 3234, B, D, E from Valkenburg
3234, C from van der Burgt 312a, F from photo Sunderland 3031, G, L from Wieringa 5281, H – K from Donis 188.
DRAWN BY HANS DE VRIES.
A REVISION OF THE GENUS SCLEROSPERMA (ARECACEAE) 79
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
Pango Mungo, Jan. 1916, J. Gossweiler 6215 (BM!);
Mayumbe, Portuguese Congo, Buco Zau Maiombe, 5
Nov. 1918, J. Gossweiler 7547 (BM!).
CONGO (KINSHASA). Bandundu , Entre la Kamtsha et
Ipamu, July 1921, H. J. R. Vanderyst 10061 (BR!);
Equateur, Besoi, 30 March 1991, M. M. Dhetchuvi
1117b (BRLU!); Nord-Kivu, Mont Bukukuha region
Mangurejipa, 1000 m, 3 June 1956, A. R. Christiaensen
1749 (BR!); Nyamakombola, 18 Oct. 1989, Terashima
84 (BR!); Orientale, Ile en aval de Basoko, 11 Jan.
1904, E. Laurent s.n. (BR!); 15 km à l’O de Yangambi;
entre la piste d’Isangi et le fleuve, 470 m, 11 Oct.
1939, J. Louis 16197 (BR!); Bambesa, 17 Nov. 1913, J.
C. C. Bequaert 120 2 (BR!); Tete/Gete (Penghe à
Irumu), forêt de l’Ituru, 22 Feb. 1914, J. C. C. Bequaert
2659 (BR!); Sud-Kivu, Bukumbi, territoire Kalehe. Km
70 route Kavumu–Walikale, 1400 m, 18 June 1955, A.
R. Christiaensen 908 (BR!).
HABITAT. Shrub layer in lowland evergreen rainforest,
ranging from forest just behind the mangrove swamp
forest, through periodically flooded forest, to valley
bottom forest at higher elevations, persisting in
secondary growth; 0 – 1,400 m.
CONSERVATION STATUS. Although this species is geo-
graphically widespread, it is highly localised with many
disjunctions. As such, the species may be classified as
Lower Risk within the sub-category Near Threatened,
but given the extent of habitat loss throughout its
range, particularly in West Africa, it could become
Vulnerable in the medium-term future.
ETYMOLOGY. The species was named after the collec-
tor of the type, Gustav Mann (1836 – 1916), a Kew
gardener and plant explorer.
VERNACULAR NAME(S). Bia (Baka, Cameroon, South
Province), Kia (Bulu, Cameroon, South Province),
Akoura (Fang, Rio Muni), Manga (Punu, Nzabi,
Lumbu, Gab on), Mangana (Angola, Cabinda),
N’Djwa (Turumbu , Congo [Kinshasa], Orientale),
Mangobo (Kingwana, Congo [Kinshasa], Orientale),
Nbya (Lega, Congo [Kinshasa], Nord-Kivu), Matukulu
(Kitembo, Congo [Kinshasa], Sud-Kivu), Mangobo
(Kiswahili, Congo [Kinshasa], Sud-Kivu), Mbia (Kir-
ega, Congo [Kinshasa], Sud-Kivu).
The following names are listed in ‘Les plantes
utiles du Gabon’ (Raponda-Walker & Sillans 1961) for
Gabon: angokolo (Mpongwè); ipovo (Galoa); amanga
Map 1. Distribution of Sclerosperma mannii, S. profiziana and S. walkeri.
80 KEW BULLETIN VOL. 63(1)
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
Fig. 2. Sclerosperma profiziana. A habit; B detail of trunk; C, D, E leaves; F basal part of petiole with leaf sheath; G various developmental
stages of immature inflorescence; H inflorescence with prophyll removed; J detail of inflorescence with very young fruits; K detail of
proximal part of inflorescence, peduncular bract partly removed, at staminate anthesis; L staminate flower from distal part of inflorescence
at staminate anthesis; M infructescence with immature fruits, peduncular bract opened; N seedling. A from photo Hall & Enti GC 36150, B
from photo Moore 9883, C – E, from Profizi 840, F, K, L, N from Gillet 279a (BR), G, M from Laurent 1054, H, J from Gillet 279a (WAG).
DRAWN BY HANS DE VRIES.
A REVISION OF THE GENUS SCLEROSPERMA (ARECACEAE) 81
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
(Nkomi, Orungu); akóra, mvyè (Fang); manga
(Éshira, Bavarama, Bavunugu, Bapunu, Balumbu,
Bavili, Baduma, Banzabi, Benga, Masangu, Ngowé);
maga (Mindumu, Ambèdè) ; makaga (Apindji,
Bavové); mbègó (Mitsogo); kóndjó (Ivéa); ingutuku
(Bakota); mèkutuku, mèkétséké (Bakèlè); and mèngo-
kulu, mékétséké (Béséki).
Some of these refer to Sclerosperma walkeri,asnodis-
tinction is made between these species by local people.
USES. The leaves are used for thatch throughout its
range either whole or in an admixture with Raphia
(Burkill 1997). In Gabon, the leaves are specifically
used for the entrance of Bwiti temples, because of the
silvery indumentum on the underside. In Cameroon,
the petioles are reported to be used for mattresses
(van der Burgt 312a). The young fruits, with the
endosperm still relatively soft, are consumed locally.
NOTES. Sclerosperma dubium was described on the basis
of a carpological collection in the Hamburg museum.
Beccari stated that he initially considered the speci-
men to belong to S. mannii. However, upon closer
examination, he considered it to be sufficiently
different with respect to the reticulation on the kernel
and the position of the embryo. The botanical
museum in Hamburg houses three samples collected
by Wölfert, all bearing the same label information,
one bottle contains a single fruit with the kernel cut
lengthwise that is obviously well developed, 20
25 mm. This specimen can easily be matched with S.
mannii, and was identified as such on the label. Two
other bottles contain a seemingly identical set of
kernels, with Sclerosperma sp. written on the label. The
dimension and the shape of the seeds match the
protologue of S. dubium. We therefore consider these
specimens to be the syntypes. The seeds in these two
samples are on average smaller than those expected for
S. mannii, but it might well be that the seeds are not yet
fully developed. Despite the slightly different colour
and external aspect of the seeds, we consider them to
fall well within the range of S. mannii, and in the
absence of any further diagnostic details, we hereby
consider S. dubium to be a synonym of S. mannii.
2. Sclerosperma profiziana Valk. & Sunder. sp. nov.
affinis S. mannii sed caule 0.1 – 2 m altus; folia integra
non praemorsa, interdum bifi d a. Infructescentiae
rhachis, 6 – 10 cm longus, fructus c. 30 in quoque.
Typus: Congo (Kinshasa), Bas-Congo, terr. Madimba,
Kisantu, ‘1913’, Gillet 279a (holotypus WAG!, isotypus
BR!, K!)
Gillet & Pâque (1910: 49) as Mabondo; De Wildeman
(1928: 309) as S. mannii; Renier (1948: 83) as S.
mabondo De Wild.; Descoings (1961:47)asS.
mabondo De Wild.; Tuley (1995: 96) as S. mabondo;
Profizi (manuscript) as S. gilletii;
Sclerosperma mabondo De Wild.; nomen nudum.
Sclerosperma gilletii Profizi (manuscript); Harley (1999:
108); Harley & Dransfield (2003:3);nomen nudum
.
Short or acaulescent, clustering palm to 6 (– 12) m
height. Stem if evident, 1 – 2 m tall, rather stout,
closely ringed with leaf scars. Leaves, undivided, very
large, deeply bifid in juveniles, ascending; sheath to
40 cm, splitting opposite the petiole, margins fi brous;
petiole robust, 60 – 100(– 400) cm long, adaxially
channelled, abaxially rounded proximally, becoming
triangular distally; rachis 150 – 200(– 450) cm long,
abaxially rounded, adaxially with a prominent ridge,
blade elongate-cuneate in outline, 20 – 60(– 140) cm
at its largest width, undivided except for the bifid apex
where the rachis is continued in a fibre and the
margins are up to 15 cm long, blade adaxially shining
dark green, abaxially glaucous and with small scales
along the veins, margins minutely toothed, transverse
veinlets not evident. Inflorescence solitary, interfoliar,
concealed among the leaf bases and sometimes
partia lly obscured by accumulated debris, spicate;
peduncle to 15 cm long, elliptic in cross-section to
3 cm wide, densely tomentose; prophyll to 23 cm long;
peduncular bract to 45 cm long; rachis at anthesis to
25 cm long, stout. Staminate flowers sepals 3, distinct 5 ×
6 mm; petals 3, distinct 5 – 8×11– 15 mm, obovate
to elliptical; stamens c. 100, filaments very short,
±triangular, anthers elongate; pistillode lacking. Pistil-
late flowers larger than the staminate, broadly ovoid;
sepals 3, connate in a 3-lobed, glabrous cupule or
margins of two sepals distinct and imbricate, some-
what angled by mutual pressure; petals 3, distinct,
asymmetrical. Rachis of infructescence 6 – 10 cm long,
bearing up to 30 fruits. Fruit globose to obovoid, 3 –
3.5 × 3.8 – 4cmto4– 4.5 × 2.5 – 3 cm (not yet
mature). Seed globose to obovoid 3 × 3.5 cm to 3.5 ×
3 cm (Fig. 2).
DISTRIBUTION. Sclerosperma p rofiziana has a clearly
disjunct distribution with a population in southwest
Ghana, and the other population in the larger
tributary of the Congo River. A photographic record
for southeast Nigeria of a Sclerosperma with undivided
or minimally bifid leaves (Tuley 1995) is not corrob-
orated by a herbarium voucher and so its presence in
Nigeria is awaiting confirmation. Map 1.
GHANA. Western Region,1– 2 miles S of Ankasa F. R.,
3 March 1971, H. E. Moore Jr. 9883 (BH!); Ankasa F. R.,
29 June 1966, J. B. Hall s.n. (K!); probably 1 – 2 miles
S of Ankasa F. R., 1966, J. B. Hall s.n. (BH!); Ankasa F.
R., 29 Dec. 1966, J. B. Hall GC 36150 (BH!, K!); Neung
North forest reserve, Adaieye hamlet (few huts), near
‘mile 7’ by mining road/track that runs W from
Tarkwa–Takoradi road, branching W just S of
Tarkwa. Fairly close to a huge open mining area,
82 KEW BULLETIN VOL. 63(1)
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
and to the northern boundary of Neung forest
reserve, 15 Nov. 2005, W. D. Hawthorne 205C 001
(FHO, WAG!); Enchi, Boi Tano Forest reserve, deep
inside Boi Tano forest reserve, about half way toward
western boundary and southern boundary with Tano
R, from Samreboi. Somewhere in or near comt ?21, 2 Nov.
2000, W. D. Hawthorne 200B 183 (FHO!, GC, WAG!).
CONGO (BRAZZAVILLE). Pool, Dist. de Kindamba, N du
village Tension, sur la rivière Moukala, 480 m, 2 April
1991, Profizi, J. P. 838 (K!); 480 m, 2 April 1991, Profizi,
J. P. 840 (BR!); 480 m, 2 April 1991, Profizi, J. P. 841
(K!).
CONGO (KINSHASA). no date, J. Gillet s.n. (BR!); April
1914, J. Gillet 351 (BR!); Bas-Congo, Terr. Madimba,
Kisantu, 1913, J. Gillet 279a (BR!, K!, WAG!); Lula
Lumene, rivière Lumene, 1902, J. Gillet 2288 (BR!);
Kasai Oriental, Rivière Movo (terr. Bakwanga), 5 Sept.
1957, L. Liben 3648 (BR!); Maniema, entre Okanga et
Bena Camba, Nov. 1896, A. Dewèvre 1095 (BR!);
Orientale, Mogandjo au N de Isangi, 10 March 1906,
M. Laurent 1054 (BR!).
ANGOLA. Lunda Norte, islands in the Luembe R, 2002,
N. Grobbelaar s.n. (K!).
HABITAT. Sclerosperma profiziana is found on relatively
dry patches in swampy areas, in valley bottom forest,
in forest that is often waterlogged or along streams.
CONSERVATION STATUS. Although this species is geo-
graphically locally common, it is highly localised with
many geographical disjunctions. As such we suggest
that, while the species may be classified as Lower Risk
within the sub-category Near Threatened, given the
extent of habitat loss throughout its range, particular-
ly in West Africa, it could become Vulnerable in the
medium-term future.
ETYMOLOGY. The species has been named after Jean-
Pierre Profizi (8 June 1954 at Marseille) to acknowl-
edge his efforts to clarify the status of this species.
VERNACULAR NAME(S). Tua (Zima, Ghana), Tu (Lari,
Téké, Soundi, Congo [Brazzaville] Pool), Tuu (Bambenga,
Congo [Brazzaville] Pool), Mabondo (Congo [Kinshasa],
Bas-Congo), Mangobo (Congo [Kinshasa], Maniema).
USES. The leaves are widely used for thatch, and
preferred to the Sclerosperma with divided leaves. In
general, smaller leaves are used for thatch, as these
are not yet damaged by the wind. In former times, the
hard kernel was used to make rings and has been the
subject of studies for its use as vegetable ivory for
button manufacturing.
NOTES. Sclerosperma with undivided leaves was consid-
ered as a mere aberrant form of S. mannii in
Anglophone taxonomic literature (Russell 1968).
The circumscription of S. mannii in the ‘Flora of
tropical West Africa’ was therefore very broad, accom-
modating the variation in leaf shape and the occa-
sional formation of a small trunk, as observed in
southwest Ghana. This species concept was also
adopted for the ‘Genera Palmarum’ treatment (Uhl
& Dransfield 1987), despite the astonishing pictures of
two extremely different leaf shapes (p. 149) based on
the collections by Moore in Ghana and Gabon in 1971
(Moore 1971). However, in Francophone literature
the name ‘mabondo’ emerged in the beginning of the
20th century to describe a Sclerosperma with undivided
leaves from the Congo tributary. This name was used
as a species epithet and ascribed to De Wildeman,
although he never validly published this name. In
1990 and 1991, Jean-Pierre Profizi made elaborate
collections of a Sclerosperma with undivided leaves in
Congo (Brazzaville). He subsequently linked his
material to “S. mabondo”, prepared a taxonomic
treatment of the species and made a first attempt to
revise of the genus Sclerosperma. However, his manu-
script was never published.
The fertile collections available for Ghana are very
limited. The inflorescences at male anthesis (Hall &
Enti GC 36150) appear to be of much more modest
dimensions than those of specimens available from
Congo. No fruit collections from Ghana are known
and, as the infructescence is obviously accrescent, this
further hampers delimitation of the species. We
therefore consider all collections with undivided
leaves that originate from Ghana and the larger
Congo tributary to belong to the same species.
The material stored in a box at BR (with the
external label ‘Gillet 279’) is a mixture of various
collections, which apparently arrived at different
dates. Two sheets, one with field tag 279, the other
with an apparent original field label 279, were
collected in 1899 (and probably arrived at BR in
1900); these represent a Sclerosperma with divided
leaves, identified as S. walkeri. A third, (at present)
unmounted, ‘sheet’ in a cover represents a Sclero-
sperma with undivided leaves. The species represented
by this collection was appar ently locally called
Mabondo: a separate piece of paper states, “elements
botaniques du Sclerosperma sp.
‘Mabondo’ du frère
Gillet de Kisantu pour le Jar Bot de Bruxelles”. This
leaf strongly resembles the two duplicates of 279
present at K and WAG; on the K and WAG sheet, the
collection date mentioned is 1913, but this date does
not figureintheBRbox.IntheKandWAG
duplicates, two inflorescences are present; similar
inflorescences are found in the BR box. These
inflorescences, the single cover sheet with undivided
leaf at BR, and the K and WAG duplicates are
renumbered to 279a. Also present in the box at BR
is a linen bag with a label mentioning the vernacular
name ‘Niagangu/Magangu’, numerous kernels, a
single fruit that fits exactly in an unlabelled infructes-
cence, and an unlabelled infructescence with mature
fruits attached. This material is renumbered as Gillet s.
n. and identified as S. walkeri.
A REVISION OF THE GENUS SCLEROSPERMA (ARECACEAE) 83
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
3. Sclerosperma walkeri A. Chev. (1931: 237); Tuley
(1995: 96); Govaerts & Dransfield (2005: 203); Val-
kenburg (2006: 321). Type: Gabon, Ngounié, mission
de Sindara, Jan. 1931, Walker s.n. (holotype P!).
Short or acaulescent, palm. Stem if evident, very short,
rather stout, closely ringed with leaf scars. Leaves,
divided, very lar ge, deeply bifid in juveniles, ascending;
sheath to 40 cm, splitting opposite the petiole, mar gin s
fibrous; petiole slender, 60 – 100(– 400) cm long,
adaxially channelled, abaxially rounded proximally,
becoming triangular distally; rachis 150 – 200 cm long,
abaxially rounded, adaxially with a prominent ridge,
leaflets (20 –)25 – 40, sub-opposite to alternate, folds
37 – 65 × 1.2 – 6 cm, the upper leaflet deeply bifid,
broadly rhomboid in outline, base of the upper leaflet
asymmetrical, 25 – 33 × 24 – 35 cm, midribs
prominent, marginal ribs next largest, blade adaxially
dark, abaxially glaucous and with small scales along the
veins, fo lds apically praemorse, margins minutely
toothed, transverse veinlets not evident. Inflorescence
solitary, interfoliar , concealed among the leaf bases
and sometimes partially obscured by accumulated
debris; peduncle, to 20 cm long, elliptic in cross-section
to 2.5 cm wide, densely tomentose; prophyll to 23 cm
long; peduncular bract to 27 cm long, rachis more than
13 cm long, stout. Staminate flowers sepals 3, distinct 6 ×
4 mm; petals 3, distinct 1 1 × 8 mm, obovate; stamens c.
100, filaments very short, ±triangular. Rach is of infructe-
scence 6 – 11 cm long, bearing up to 30 fruits. Fruit
globose, 4 – 5×3– 3.5 cm. Seed globose, 2.1 – 2.6 × 2.6
– 2.9 cm (Fig. 1 1F–L).
DISTRIBUTION. Sclerosperma walkeri is found in the
interior of Gabon and along the lower reaches of
the Congo River and as such confined within the
eastern distribution range of S. mannii. Map 1.
GABON. Ngounie´, mission de Sindara, 5 Jan. 1931, A.
A. Walker s.n. (P!); Saint Martin, 1938, A. A. Walker s.n.
(BM!, BR!); Waka National Park, 15 km on the road
Evouta to Egoubi forestry camp, 400 m, 5 April 2004,
J. J. Wieringa 5281 (LBV!, WAG!); Waka National Park,
4 July 2005, T. C. H. Sunderland 3031 (LBV,WAG!);
Ogooué-Lolo, Chantier CEB, 6 km on road Lelama to
Okondja, E of road Okondja-Franceville, 300 m, 2
Nov. 2005, M. S. M. Sosef 2206 A (LBV, WAG!); 300 m,
2 Nov. 2005, M. S. M. Sosef 2206 B (LBV, WAG!).
CONGO (KINSHASA). Bas-Congo, no date, J. Gillet s.n.
(BR!); Kisantu, 1899, J. Gillet 279 (BR!); Lusanga
Sundi, 350 m, 14 Feb. 1940, C. Donis 188 (BR!);
Equateur, Djoa, 17 May 1958, C. Evrard 4081 (BR!, K!);
Kilemba, 26 May 1913, Broun s.n. (BR!); Orientale,
Près rivière Longwele à 1 jour de Yalibwa (env.
Yangambi), 15 Jan. 1948, J. J. G. Léonard 1614 (BR!).
HABITAT. Shrub layer in lowland evergreen rainforest,
ranging from swamp forest, periodically flooded forest
to lower slopes on terra firme, persisting in secondary
growth; 300 – 400 m.
CONSERVATION STATUS. On the basis of its restricted
range in Central Gabon and the lower reaches of the
Congo River, and the pressures of its native habitat,
this species can be considered Vulnerable.
ETYMOLOGY. Th e specie s was named after André
Raponda-Walker (1871 – 1968), who collected the type
specimen.
VERNACULAR NAMES. Manga (Ivili, Gabon Ngounié),
Mbègho (Mitsogo, Gabon, Ngounié). Niagangu, Mag-
angu (Congo [Kinshasa], Bas-Congo), Lifete, Mpete
(Congo [Kinshasa], Equateur).
USES. The leaves are widely used for thatch through-
out its range, and locally used also for matting and
walls. In areas with large populations of lowland
gorilla (Gorilla gorilla gorilla), it is rare to find mature
infructescences intact because the fruits are con-
sumed by these forest primates.
NOTES. The type specimen in Paris consists of an
undeveloped juvenile leaf, a number of immature
fruits with decayed kernels, a fruit that has started to
germinate, and an infructescence stalk. The fruits
differ from those of S. mannii in not being depressed
apically, a difference that is mentioned as a diagnostic
feature. In S. mannii collections too, however, fruits
can be found that are not apically depressed. These
germinating S. mannii fruit are reported to have
another feature assumed to be diagnostic of S. walkeri:
a cavity in the kernel. This should be attributed,
however, to the mobilisation of the endosperm for
germination. Similar cavities were found in germinat-
ing seeds of S. mannii collected by van Valkenburg.
The leaf segments being alternate, as opposed to
opposite in S. mannii, is equally invalid as a diagnostic
feature and was actually contradicted by the illustra-
tion accompanying the protologue of S. mannii
showing both alternate and opposite leaflets. Notwith-
standing that the protologue of S. walkeri does not
contain any valid distinguishing characters, the type
specimen retains its value because of the infructe-
scence stalk that is present on the type sheet. This
infructescence stalk clearly demonstrates the more
robust character of both the peduncle and the
rachis, which is also found in other specimens of
Sclerosperma with divided leaves from the same area
and further east; these leaves have significantly more
leaf segments than those of true S. mannii. Well-
developed leaves of S. walkeri have 25 – 40 le af
segments, which are relatively narrow (up to 6 cm
wide), whereas in S. mannii, the leaves have usually 8 –
17 leaf segments that are mostly 6 – 9 cm wide. The
infructescence of S. walkeri is characterised by a more
robust peduncle, its rachis is equally more robust and
longer than in S. mannii, and its fruits are of larger
dimensions.
84 KEW BULLETIN VOL. 63(1)
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
Sclerosperma Indet
West Africa, no date, A. Woermann 603/11 (HBG!) [a
single kernel only];
CONGO (BRAZZAVILLE). Pool, Village
Moussélé, 22 Dec. 1992, M. Bitsindou 314 (BRLU!)
[incomplete leaf only].
Acknowledgements
We are grateful to the staff and curators of BH, BM,
BR, BRLU, FHO, HBG, K, LBV, MO and P for
providing material on loan. Hans-Helmut Poppen-
dieck and Bernd Frauendorfer have been instrumen-
tal in unearthing the Wölfert collections from the
Botanical Museum in Hamburg. Xander van der
Burgt, Carel Jongkind and William Hawthorne made
an extra effort to collect Sclerosperma material from
Cameroon, Liberia and Ghana. Hans de Vries pro-
duced the elegant plates that illustrate this article.
The authors wish to thank the Conseil National des
Parcs Nationaux at Libreville for granting us permis-
sion to work in Moukalaba Doudou and Waka
National Parks. JvV’s field trip in April 2005 to the
Moukalaba Doudou National Park was sponsored by
National Geographic Society grant 7759-04 entitled
‘Botanical diversity of altitude zones in the Monts
Doudou’ (a portion of Central African BOtanical
NETwork [CABONET]). JvV’s visit to Kew to finalise
the manuscript was financially supported by the MOABI
foundation. TS is grateful to the Central African
Regional Program for the Environment (CARPE),
notably Dr John Flynn, for funding the work of the
Smithsonian Institution in Central Africa. WCS-Gabon,
particularly Brian Curran and Malcolm Starkey, are
acknowledged for logistical support in the field. Special
thanks are extended to Michael Balinga of FOREP for
continued collaboration and field assistance.
References
Aedo, C., Tallería, T. & Velayos, M. (eds) (1999). Bases
documentales para flora de Guinea Ecuatorial:
plantas vasculares y hongos. CSIC, Real Jardín
Botánico, Madrid.
Asmussen, C. B., Dransfield, J., Deickmann, V., Barfod,
A. S., Pintaud, J. C. & Baker, W. J. (2006). A new
subfamily classi fication of the palm family (Areca-
ceae): evidence from plastid DNA phylogeny. Bot. J.
Linn Soc. 151: 15 – 38.
Burkill, I. H. (1997). The useful plants of West
Tropical Africa. 2nd Edition. Vol. 4. Families M –
R. Royal Botanic Gardens, Kew.
Chevalier, A. (1931). Sur un nouveau Sclerosperma du
Gabon. Rev. Bot. Appl. Agric. 11: 236 – 239.
De Wildeman, E. (1928). Plantae Bequaertianae. Vol.
IV, fasc. III, pp. 309 – 452. A. Buyens, Gand; J.
Lechevalier, Paris.
Descoings, B. (1961). Inventaire des plantes vascu-
laires de la république du Congo (déposées dans
l’Herbier de l’Institut d’Etudes Centre-Africaines à
Brazzaville). Office de la recherche scientifique et
technique outre-mer, Institut d’Etudes Centre-
Africaines, laboratoire de botanique, Brazzaville.
Dransfield, J. & Uhl, N. W. (1998). Palmae. In: K.
Kubitzki (ed.), Families and genera of vascular
plants. Volume IV. Flowering plants. Monocotyle-
dons. pp. 306 – 389. Springer Verlag, Berlin.
____, Tesoro, F. O. & Manokaran, N. (eds.) (2002).
Rattan: current research issues and prospects for
conservation and sustainable development. Non-
wood forest products 14. FAO, Rome.
____, Uhl, N. W, Asmussen, C. B., Baker, W. J., Harley,
M. M. & Lewis, C. E. (2005). A new phylogenetic
classification of the palm family, Arecaceae. Kew Bull.
60: 559 – 569.
Drude, O. (1895). Die Palmenflora des tropischen
Afrika. Bot. Jahrb. Syst. 21: 108 – 136.
Gillet, J. & Pâque, E. (1910). Plantes principales de la
Région de Kisantu. Leur nom indigène, leur nom
scientifique, leurs usages. Ann. Mus. Congo Belge,
Bot. Sér. V, Bas-et-Moyen-Congo. Notes Botaniques
sur la Région du Bas-et-Moyen-Congo. (Fascicule I.)
Govaerts, R. & Dransfield, J. (2005). World Checklist
of Palms. Royal Botanic Gardens, Kew.
Guinea López, E. (1946). Ensayo geobotánica de la
Guinea continental española. Dirección de agricul-
tura de los Territorios Españoles del Golfo de
Guinea, Madrid.
Harley, M. M. (1999). Palm pollen: overview and
examples of taxonomic value at species level. In: A.
Henderson & F. Borchsenius, (eds.). Evolution,
variation, and classification of palms. Mem. New
York Bot. Gard. 83: 95 – 120.
____ & Dransfield, J. (2003). Triporate pollen in the
Arecaceae. Grana 42: 3 – 19.
Hua, H. (1895). Les dernières collections de M.
Dybowski; quelques espèces rares ou nouvelles.
Bull. Mus. Hist. Nat. (Paris) 1: 314 – 315.
IUCN (2001). IUCN Red List Categories: Version 3.1.
IUCN, Species Survival Commission, Gland, Swit-
zerland and Cambridge, U.K.
Kerchove de Denterghem, O. de. (1878). Les Palm-
iers. J. Rothschild, Paris.
Letouzey, R. (1978). Notes phytogéographiques sur les
Palmiers du Cameroun. Adansonia, sér . 2, 18: 293 – 325.
Mann, G. & Wendland, H. A. (1864). On the Palms of
Western Tropical Africa. Trans. Linn. Soc. London
24: 421 – 440.
Martelli, U. (1934). Generi, specie e varietà nuove di
palme gerontogee della tribu Areacaeae lasciate
inedite dal Dr Od. Beccari ed ordinate a cura di
U. Martelli. Atti Soc. Tosc. Sci. Nat. Pisa Processi
Verbali 44: 114 – 176.
A REVISION OF THE GENUS SCLEROSPERMA (ARECACEAE) 85
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
Moore, H. E. (1971). Wednesdays in Africa. Principes
15: 111 – 119.
Pellegrin, Fr. (1938). La Flore du Mayombe [d’après
les récoltes de M. Georges Le Testu]. Troisième
partie. [Extrait des Mém. Soc. Linn. Normandie, N.
Sér. Bot. 1
er
vol. 4
e
fasc.]
Raponda-Walker, A. & Sillans R. (1961). Les plantes
utiles du Gabon. Paul Lechevalier, Paris.
Renier, M. (1948). Flore du Kwango. Tome 1. Mission
des Jésuites, Kisantu, Congo.
Russell, T. A. (1968). Palmae. In: J. Hutchinson, J. M.
Dalziel, & F. Hepper (eds.), Flora of West Tropical
Africa. 2nd edition Volume 3, Part 1, pp. 159 – 169.
Crown Agents for Overseas Governments and
Administrations, London.
Sunderland, T. C. H. (2000). The taxonomy, ecology
and utilisation of African rattans (Palmae: Calamoi-
deae). PhD Thesis. University College, London and
the Royal Botanic Gardens, Kew.
Tomlinson, P. B. (1962). Palms of Africa. Principes 6:
96 – 103.
Tuley, P. (1995). The palms of Africa. The Tendrine
Press, Zennor, St. Ives, Cornwall, U.K.
Uhl, N. W. & Dransfield, J. (1987). Genera Palmarum:
a classification of palms based on the work of H. E.
Moore Jr. The L. H. Bailey Hortorium and The
International Palm Society. Allen Press, Lawrence,
Kansas, U.S.A.
Van Valkenburg, J. L. C. H. (1997). Non-timber forest
products of East Kalimantan — potentials for sustain-
able forest use. (Tropenbos Series 16). The Tropen-
bos Foundation, Wageningen, The Netherlands.
____ (2006). Palmae. In: M. S. M., Sosef et al.Check-list
des plantes vasculaires du Gabon/Checklist of Gabon-
ese vascular plants. Scripta Bot. Belg. 35: 320 – 321.
____ & Sunderland, T. C. H. (2008). A revision of the
genus Podococcus (Arecaceae). Kew Bull., in press.
____, Sunderland, T . , Ngok Banak, L. & Issembé, Y. (2007).
Sclerosperma and Podococcus in Gabon. Palms 51: 77 – 83.
Wright, C. H. (1902). Palmae. In: W. T. Thiselton-Dyer,
(ed.). Flora of Tropical Africa. Volume 8, pp. 97 –
127. Lovell Reeve & Co, London.
86 KEW BULLETIN VOL. 63(1)
© The Board of Trustees of the Royal Botanic Gardens, Kew, 2008
