Flora of tropical East Africa - Balanitaceae (2003) (Flora of Tropical East Africa)

32 Pages·2003·0.45 MB·English

by  H. J. Beentje

LIST OF ABBREVIATIONS
A.V.P.=O.Hedberg, Afroalpine Vascular Plants;
B.J.B.B.=Bulletin du Jardin Botanique de l’Etat, Bruxelles; Bulletin du Jardin Botanique
Nationale de Belgique;
B.S.B.B.=Bulletin de la Société Royale de Botanique de Belgique;
C.F.A.= Conspectus Florae Angolensis;
E.J.=A.Engler, Botanische Jahrbücher für Systematik, Pflanzengeschichte und
Pflanzengeographie;
E.M.=A.Engler, Monographieen Afrikanischer Pflanzen-Familien und Gattungen;
E.P.=A.Engler, Das Pflanzenreich;
E.P.A.=G.Cufodontis, Enumeratio Plantarum Aethiopiae Spermatophyta; in B.J.B.B. 23,
Suppl. (1953) et seq.;
E. & P. Pf.=A.Engler & K.Prantl, Die Natürlichen Pflanzenfamilien;
F.A.C.=Flore d’Afrique Centrale (formerly F.C.B.); F.C.B.=Flore du Congo Belge et du
Ruanda-Urundi; Flore du Congo, du Rwanda et du Burundi;
F.D.O.A.=A.Peter, Flora von Deutsch-Ostafrika;
F.F.N.R.=F.White, Forest Flora of Northern Rhodesia;
F.P.N.A.=W. Robyns, Flores des Spermatophytes du Pare National Albert;
F.P.S.=F.W.Andrews, Flowering Plants of the Anglo-Egyptian Sudan or Flowering
Plants of the Sudan;
F.P.U.=E.Lind & A.Tallantire, Some Common Flowering Plants of Uganda;
F.R.=F.Fedde, Repertorium Speciorum Novarum Regni Vegetabilis;
F.S.A.=Flora of Southern Africa;
F.T.A. =Flora of Tropical Africa;
F.W.T.A.=Flora of West Tropical Africa;
F.Z.=Flora Zambesiaca;
G.F.P.=J.Hutchinson, The Genera of Flowering Plants;
G.P.=G.Bentham & J.D.Hooker, Genera Plantarum;
G.T.=D.M.Napper, Grasses of Tanganyika;
I.G.U.=K.W.Harker & D.M.Napper, An Illustrated Guide to the Grasses of Uganda;
I.T.U.=W.J.Eggeling, Indigenous Trees of the Uganda Protectorate;
J.B.=Journal of Botany;
J.L.S.=Journal of the Linnean Society of London, Botany;
K.B.=Kew Bulletin, or Bulletin of Miscellaneous Information, Kew;
K.T.S.=I.Dale & P.J.Greenway, Kenya Trees and Shrubs;
K.T.S.L.=H.J.Beentje, Kenya Trees, Shrubs and Lianas;
L.T.A.=E.G.Baker, Leguminosae of Tropical Africa;
N.B.G.B.=Notizblatt des Botanischen Gartens und Museums zu Berlin-Dahlem;
P.O.A.=A.Engler, Die Pflanzenwelt Ost-Afrikas und der Nachbargebiete;
R.K.G.=A.V.Bogdan, A Revised List of Kenya Grasses;
T.S.K.=E.Battiscombe, Trees and Shrubs of Kenya Colony;
T.T.C.L.=J.P.M.Brenan, Check-lists of the Forest Trees and Shrubs of the British Empire
no. 5, part II, Tanganyika Territory;
U.K.W.F.=A.D.Q.Agnew (or for ed. 2, A.D.Q.Agnew & S.Agnew), Upland Kenya Wild
Flowers;
U.O.P.Z.=R.O.Williams, Useful and Ornamental Plants in Zanzibar and Pemba;
V.E.=A.Engler & O. Drude, Die Vegetation der Erde, IX, Pflanzenwelt Afrikas;
W.F.K.=A.J.Jex-Blake, Some Wild Flowers of Kenya;
Z.A.E.= Wissenschaftliche Ergebnisse der Deutschen Zentral-Afrika-Expedition 1907–
1908, 2 (Botanik).
FAMILIES OF VASCULAR PLANTS REPRESENTED IN THE FLORA OF
TROPICAL EAST AFRICA
The family system used in the Flora has diverged in some respects from that now in use
at Kew and the herbaria in East Africa. The accepted family name of a synonym or
alternative is indicated by the word “see”. Included family names are referred to the one
used in, the Flora by “in” if in accordance with the current system, and “as” if not. Where
two families are included in one fascicle the subsidiary family is referred to the main
family by “with”.
Foreword and preface (£3.00) Glossary (£23.50) Index of Collecting Localities (£18.50)
PTERIDOPHYTA
Actmiopteridaceae (£2.30) Grammitidaceae Polypodiaceae (£10.00)
Adiantaceae (£15.00) Hymenophyllaceae Psilotaceae (£1.70)
Aspleniaceae Isoetaceae Pteridaceae (£8.50)
Azollaceae (£1.70) Lomariopsidaceae (£10.00) Salviniaceae (£1.40)
Blechnaceae Lycopodiaceae Schizaeaceae (£3.40)
Cyatheaceae Marattiaceae (£1.70) Selaginellaceae
Davalliaceae (£1.70) Marsileaceae (£6.00) Thelypteridaceae
Dennstaedtiaceae (£6.50) Oleandraceae (£6.00) Vittariaceae (£2.95)
Dryopteridaceae Ophioglossaceae (£7.00) Woodsiaceae (£8.00)
Equisetaceae (£1.70) Osmundaceae (£1.70)
Gleicheniaceae (£2.30) Parkeriaceae (£1.70)
GYMNOSPERMAE (£3.00)
Cupressaceae Cycadaceae Podocarpaceae
ANGIOSPERMAE
Acanthaceae Aponogetonaceae (£3.90)
Agavaceae Aquifoliaceae (£1.50)
Aizoaceae (£4.50) Araceae (£10.20)
Alangiaceae (£1.50) Araliaceae (£3.00)
Alismataceae (£3.00) Arecaceae—see Palmae
Alliaceae (£4.00) Aristolochiaceae (£3.00)
Aloaceae (£14.50) Asclepiadaceae—see Apocynaceae
Amaranthaceae (£22.00) Asparagaceae
Amaryllidaceae (£5.10) Asphodelaceae (£6.00)
Anacardiaceae (£8.50) Asteraceae—see Compositae
Ancistrocladaceae (£1.85) Avicenniaceae—as Verbenaceae
Anisophyllaceae—as Rhizophoraceae
Annonaceae (£10.50) Balanitaceae (£6.00)
Anthericaceae (£11.50) Balanophoraceae (£1.95)
Apiaceae—see Umbelliferae Balsaminaceae (£11.80)
Apocynaceae Basellaceae (£1.50)
Parti (£20.50) Begoniaceae
Part 2 Berberidaceae (£1.50)

© 2003 Royal Botanic Gardens, Kew
FLORA OF TROPICAL EAST AFRICA
BALANITACEAE
MARTIN J.S.SANDS
Deciduous or semi-evergreen spiny trees or shrubs. Spines simple or branching, derived
from the distal of 2 or more buds, axillary or at a varying supra-axillary interval1. Leaves
alternate or spirally arranged, either reduced to simple, minute and usually triangular,
mostly caducous, exstipulate scale-leaves, or bifoliolate, sessile or petiolate, with a linear
or triangular, sometimes persistent, terminal foliole2; stipules caducous or persistent,
triangular to filiform, entire. Flowers actinomorphic, sepals and petals free, bisexual, 4–5-
merous, rarely solitary, usually in a 2–many-flowered, bracteate, mostly cymose and
subumbellate to fasciculate inflorescence, borne at spineless or spiniferous nodes on the
stem or spines. Sepals imbricate, often reflexed and caducous, one or both margins
glabrous, silky-hairy within. Petals spreading, sometimes reflexed, usually irregular, bent
or contorted at the apex, yellow to green, glabrous outside, glabrous or hairy within.
Stamens 8–10, free, glabrous; anthers dorsifixed, 2-thecous, dehiscing by longitudinal
slits. Disc intrastaminal, annular, succulent, corrugated and minutely papillose,
surrounding the base of the ovary. Ovary superior, hemispherical to ovoid, 4–5-locular,
each locule containing 1 pendulous ovule; style simple, terminal, glabrous, stigma small
and simple. Fruit a 1-seeded drupe on a thickened pedicel; exocarp leathery or brittle,
mesocarp variable from pulpy to fibrous and oily, endocarp hard, often woody, splitting
distally at germination; seed with plano-convex cotyledons.
Monotypic.
For the purpose of this Flora, Balanitaceae is recognized as an independent family.
The genus Balanites has been variously classified and its supra-generic position
continues to be debated. Recent molecular work by Sheahan & Chase (Syst. Bot. 25(2):
380 (2000)) has shown that Balanites is embedded in the Tribuloid clade within
Zygophyllaceae; the Angiosperm Phylogeny Group (Ann. Missouri Bot. Gard., 85:531–
553 (1998)) also include Balanites in Zygophyllaceae.
BALANITES
Delile, Descr. Egypte, Hist. Nat. 2:221, t. 28, 1 (1813); Sands in K.B. 56:1–128 (2001)
Description as for the family.
Nine species, two species in India and Burma, the others distributed throughout much
of Africa, with one also occurring in Yemen and another extending into Arabia and the
Jordan valley.
Several species of Balanites are of economic importance in Africa. A major use is that
of the fruit of several species, especially the ‘desert date’ (B. aegyptiaca) which is edible
and yields a valuable oil as well as the pharmaceutically important steroid, diosgenin, and
Flora of tropical East Africa 2
a saponin-glucoside toxic to cold-blooded animals that are hosts to guinea-worm and
stages of bilharzia. The leaves and inflorescences have several uses including as
vegetables. The wood of most species has many uses such as furniture making and
turnery, and bark and roots especially are variously used in traditional medicine. All
aerial parts are browsed by livestock.
1 distance above the subtending leaf
2 vestigial terminal leaflet
KEY TO FLOWERING MATERIAL
Balanites sp. ‘Omo Valley’ is known only from sterile material and therefore not
included in this key.
1. Flowers 5-merous; petals hairy within 2
Flowers 4- or 5-merous; petals glabrous within 3
2. Tree usually more than 30 m high; spines forked or branching several times, the 1. B.
spine-branches usually more or less equal; fruit 8–12 cm long wilsoniana
Shrub or tree less than 20 m (rarely 25 m) high; spines simple or branching with 2. B.
the spine-branches usually unequal; fruit usually less than 6 cm long, rarely to 8 maughamii
cm
3. Spines not bearing flowers or leaves; ovary elongating early in development 3. B.
aegyptiaca
Spines bearing flowers or leaves; ovary not or scarcely elongating in early 4
development
4. Flowers 5-merous 4. B.
pedicellaris
Flowers 4-merous 5
5. Spines arising (1–)2–5(–10) cm above the subtending leaf axil; secondary 5. B.
spines present; ovary hairy or glabrous rotundifolia
Spines arising 0.5–2 cm above the subtending leaf axil; spines sometimes 6. B. glabra
branching but secondary spines absent; ovary glabrous
KEY TO STERILE SPECIMENS
This key assumes the presence of spines or at least a field report of their occurrence.
Spinules are small secondary spines borne on the primary spine and usually at a wide
angle to it.
1. Spines naked without leaves or flowers or their scars 2
Spines bearing leaves or exhibiting leaf and/or flower or inflorescence scars 5
2. Small shrub less than 0.5 m high; spinules present; leaflets sharply acute or B. sp. ‘Omo
apiculate 7. Valley’
Flora of tropical East Africa 3
Large shrub or small tree; spinules absent, leaflets obtuse, rounded or bluntly 3
acute to acuminate
3. Spines usually forked or branching with deflection of the primary spine, at least 4
on the trunk and main branches
All spines simple, unbranched, or branch-spines rare, and short clearly 3. B.
subordinate without deflection of the primary spine aegyptiaca
4. Large tree usually more than 30 m high; forked or branching spines mostly borne 1. B.
on the trunk and branches, infrequent and simple on branchlets; remains or scars wilsoniana
of inflorescences supra-axillary, up to 5(–10) mm above the axil; stipules
caducous; indumentum of petioles and young growth silvery-grey
Tree rarely exceeding 20 m high; spines on younger stems as well as on the 2. B.
upper trunk and branches; remains or scars of inflorescences axillary; stipules maughamii
usually persistent; indumentum of petioles and young growth yellowish- or
greyish-green to buff
5. Spines sometimes branching, tending to widen dorsiventrally at the base, 0.5–3 6. B. glabra
cm above the axil; spinules absent; foliage-leaves infrequent; scale-leaves
occurring on the parent stem, sometimes persistent
Spines frequently branching, scarcely widening at the base, 0.5–10 cm above the 6
axil; spinules often present; foliage-leaves frequent; scale-leaves only evident on
growth or secondary spines
6. Primary spine and branch-spine/spinule supra-axillary intervals 0.5–1.2(–2.6) cm 4. B.
and 1–2 mm respectively; leaflets broadly obovate to spathulate, cuneate; scale- pedicellaris
leaves occurring on the spinules, or sometimes on growth, up to 1.3 mm long;
stipules caducous
Primary spine and branch-spine/spinule supra-axillary intervals (1–)2–5(–10) cm 5. B.
and (2–)4–7 mm respectively; leaflets usually orbicular to broadly obovate, rotundifolia
rounded or broadly cuneate; scale-leaves occasional on young growth, 2–3 mm
long; stipules often persistent
Flora of tropical East Africa 4
1. B. wilsoniana Dawe & Sprague in Dawe, Bot. Miss. Uganda Prot: 14, 23 & 40 (April
1906) & (desc. expans.) in J.L.S., Bot. 37:506 (Nov. 1906); Z.A.E. 2:422 & t. 47 (1910);
I.T.U.: 230 (1940) & ed. 2, with Dale: 407 (1952); Gilbert in F.C.B. 7:66 (1958) pro
parte; Hamilton, Uganda For. Trees: 194 (1981); Sands in K.B. 56:20, t. 5, map 1 (2001).
Type: Uganda, Toro District, Kibale Forest, Dawe 511 (K!, holo.)
Usually evergreen tree 30–45(–50) m high with an irregular, sometimes open crown;
trunk up to 1.2 m in diameter, sometimes buttressed and usually very deeply fluted; bark
smooth to irregularly rough and warty, yellowish to light brown, sometimes with
scattered small black spheres of hardened resinous exudate; branchlets frequently from
swollen nodes, often deciduous leaving a conical pit, glabrous or puberulous and
glabrescent, yellowish-green occasionally becoming blackened. Spines borne at a wide
angle on the trunk and branches, up to 15 cm long and 9 mm diameter at the base,
without leaves or flowers, forked or branching several times, the branch-spines subtended
by scale-leaves when young; spines on flowering and some sterile branchlets infrequent,
usually simple and short, up to 1(–2) cm long borne 5–12 mm above the axil; spinules
absent. Leaves on sterile and fertile branchlets, usually persistent; stipules narrowly
triangular, 0.2–0.5 mm long, soon caducous; petiole 1–3.1 cm long; petiolules 0.3–1.8 cm
long; leaflets ovate to ovate-elliptic with the inner half often slightly smaller than the
outer, 5.8–11.5 cm long, 2.7–7.5 cm wide, acute to acuminate, often developing a drip-tip
1.5–3 cm long on sterile shoots, more or less equally rounded or abruptly cuneate, the
two sides sometimes joining the petiole 1–2 mm apart, membranous, eventually
coriaceous; venation often prominent, glabrous, but sparsely puberulous on the main vein
beneath at first; foliole 0.3–3(–14) mm long, sometimes early caducous. Inflorescence 2–
5(–8)-flowered, subfasciculate or condensed, often an umbellate cyme, 0.5–1 cm from
the leaf-axil on stems of the current year, or several on an axillary, usually leafless shoot,
grey-puberulous to tomentellous; peduncle absent or up to 18 mm long. Flowers 5-
merous; sepals elliptic to ovate, remaining concave, 3–6 mm long, 1.5–3.7 mm wide,
acute, usually caducous as the bud opens, shortly grey-puberulous to tomentellous
outside, the glabrous margin narrow; petals pale yellowish green, oblong-elliptic to
oblanceolate, becoming reflexed at anthesis, 6–10 mm long, 1.5–2.5 mm wide, acute, the
glabrous tip sometimes slightly contorted, villous within; stamens 10, spreading-erect;
anthers 1–1.5 mm long, 0.5–1 mm wide; ovary 1–2 mm high, densely white- to grey-
hairy; style 1–1.5 mm long. Fruit only one developing from an inflorescence, soon
elongating in early development, brown to yellow at maturity, ovoid or ellipsoid to
broadly fusiform, (6.5–)8–12 cm long, (3.5–)5.8–7 cm wide, tapering to obtuse ends,
glabrous and dark, pulpy, oily and malodorous within; seed loose at maturity, cream,
ellipsoid to fusiform, up to 4.3 cm long.
var. wilsoniana; Sands in K.B. 56:25, t. 5/a–k, map 1 (2001)
Pedicels up to 1.3 cm long at an thesis. Petals villous within, not exceeding 7 mm
long.
UGANDA. Bunyoro District: Budongo Forest, 1935, Eggeling 1634! & 15 May 1941,
Thomas 3894!; Mengo District: Mabira Forest, Mulange, Jan.–Feb. 1920, Dummer 4396!
DISTR. U 2, 4; from Ivory Coast in the west to Uganda and southwards into Congo
(Kinshasa)
HAB. Moist forest; 1100–1200 m
Flora of tropical East Africa 5
NOTES. A var. mayumbensis occurs in Congo (Brazzaville) and Angola, and var.
glabripetala in Nigeria. They are distinct in the longer petals and the longer pedicels at
anthesis; var glabripetala has glabrous petals..
Many specimens of B. maughamii subsp. acuta from Kenya and Tanzania were
formerly identified as B. wilsoniana.