for 14 Rubiaceae weed species of western and - Agritrop

for 14 Rubiaceae weed species
of western and central Africa.
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The biology and ecology of weed species must be fully defined before developing
strategies to control them. An identification key was developed for Rubiaceae
weed species based on vegetative characters, as is a followup to the key already
drawn up for the Sida L. genus (VIAROUGE et a!., 1995).
The identification
key
This key is meant to be an aid for the
identification of 14 Rubiaceae spe­
cies of western and central Africa,
belonging to five different genera
(Table 1): D io d ia Linn., Kohautia
Cham. & S chlecht., M it r a c a r p u s
Z u c c ., O l d e n l a n d i a L in n ., and
S p e rm a c o c e D ill, ex L. (form erly
Borreria G. F. W. Mey.).
Identification characters
Data for this identification key were
obtained from studies carried out on
various flo ra species in d iffe re n t
countries, i.e. in Senegal (BERHAUT,
1967), West Africa (HUTCHINSON
et a i , 1958), Togo (BRUNEL, 1984),
the Indian Ocean region (BOSSER et
ai., 1989) and Guadeloupe (FOURNET, 1978). In addition, agronomic
reference w orks were consulted,
along with an analysis of herbarium
J. SALAMERO, P. MARNOTTE,
T. IE BOURGEOIS, A. CARRARA
CIRAD-CA, BP 5 0 3 5 ,
3 4 0 3 2 M ontpellier, France
Agriculture et développem ent ■
Rubiaceae family
General characteristics
T h e R u b ia c e a e f a m i l y is e x t r e m e ly la rg e , i n c l u d i n g 5 0 0 g e n e ra a n d n e a r ly
7 00 0 species (H E Y W O O D , 1978). It is a c o s m o p o lita n fa m ily , m a in ly o f tro p ic a l
species, but the herbaceous species are more c om m o n in temperate regions.
The leaves are entire, opposite, sometimes w horled, and have no stipules. The flowers
a re r e g u la r . T h e c a l y x is g a m o s e p a l a n d its b a s a l p a r t is fu s e d w i t h th e
ovary. The coro lla is formed by 4-5 petals fused at the base. There is the same number
o f stamens and petals. They are fused in the coro lla tube or throat. The ovary generally
consists o f 1-10 loculi. The fru it is a capsule, berry or drupe. The seeds contain a fleshy
albumen and are often w inged.
Economic importance
Rubiaceae species are of considerable econom ic im portance. The best know n products
are coffee (Coffea) and q u in in e (Cinchona). Some genera are used to pro du ce dyes
(Rubia, Uncaria), or are tapped for their m edicinal properties (Cephaelis). There are also
m any ornamental plants in this fam ily, such as Gardenia and Ixora.
samples from CIRAD and the Institut
de Botanique (Montpellier, France).
Eight vegetative characters (Table 2)
are taken into consideration in the
key: stem (shape, pubescence), leaf
(phyIlotaxis, lamina shape, pubes­
cence, margin), stipular sheath (size,
size of stipule segment).
All identification characters are rea­
dily visible and no special botanical
k n o w le d g e is re q u ire d to assess
them.
Special issue - M a y 19 9 7
Several keys w ere d ra w n up by
investigating different combinations
of characters (Table 2), but not all
were s u ita b le fo r id e n tify in g the
14 species. A single key, applicable
for all cases, was finally developed.
However, it is sometimes complica­
ted to differentiate species belonging
to the same genus because of varia­
bility in the vegetative characters. In
such cases, accurate identifications
can be made on the basis of flower
traits.
Table 1. Liste of species and synonyms.
Starting point:
Synonym
Diodia sarmentosa Swartz
Diodia scandens Swartz, sensu FWTA, ed 2
Diodia breviseta Bentham
Diodia pilosa Schumacher & Thonning
Diodia ripatia Sagot
Diodia rubricosa Chev
Spermacoce palmetorum DC.
Spermacoce pilosa (Schumacher & Thonning) DC.
Spermacoce spinosa Loefl.
Kohautia grandiflora DC.
Oldenlandia grandiflora (DC.) Hiern
Kohautia senegalensis Cham. Schlecht
Oldenlandia senegalensis (Cham. & Schlecht) Hiern
Oldenlandia confusa Hutch. & Dalz
Mitracarpus villosus (Swartz) DC.
Mitracarpus scaber Zuccarini
Mitracarpus senegalensis DC.
Mitracarpus hirtus (Swartz) DC., sensu FL.Bras.
Mitracarpus verticillatus (Schumacher & Thonning) Vatke
Spermacoce hirta L.
Spermacoce villosa Swartz
Staurospermum verticillatum (Schum. Thonn.)
Oldenlandia corymbosa Lin.
Hedyotis alsinaefolia Br.
Hedyotis burmanniana Br.
Hedyotis corymbosa (L.) Lamk.
Hedyotis biflora Roth.
Hedyotis graminicola Kuz.
Hedyotis intermedia W et A.
Cerontogea biflora Cham & Schlecht.
Oldenlandia alsinifolia Don.
Oldenlandia biflora Lam.
Oldenlandia herbacea DC.
Oldenlandia ramosa Roxb.
Oldenlandia scabrida DC.
In the oblong to e llip tic a l lam ina
group, Mitracarpus villosus is distin­
guished by its square stem with roun­
ded angles.
If the stem angles are sharp, then it is
S. chaetocephala.
Leaf pubescence has to be assessed if
the stem angles are winged. S. ocy­
moides has glabrous leaves, w h ile
those of 5. latifolia are pubescent and
those of D. sarmentosa are scabrous
on the upper surface and pubescent
underneath.
In the linear lamina group, the leaves
of S. verticillata are arranged in pseudo-whorls.
Oldenlandia herbacea (Linn.) Roxb.
Hedyotis herbacea Linn.
Oldenlandia Heynei G.Don
Oldenlandia Virgata Chev.
Spermacoce chaetocephala DC.
Borreria chaetocephala (DC.) Hepper
Borreria compacta Berhaut
Borreria compacta (Hiern) K. Schumann
Borreria ruclliae (F.W.T.A. not DC. ) K. Schumann
Spermacoce compacta (Hiern)
Spermacoce hebecarpa (A. Richard) O liv. var. minor Hiern
Spermacoce hebecarpa Hotch. ex A. Richard Oliver
Spermacoce kotschyana Oliver
Spermacoce latifolia Aublet
Borreria alata (Aublet) DC.
Borreria bartilingiana DC.
Borreria perrottettii DC.
Borreria latifolia Aublet K. Schumann
Borreria scaberrima Bold.
Spermacoce coerulescens Aublet
In the group of species with opposite
leaves, the size of the dentate stipulary collar is the key feature. Among
the fo u r species w ith a c o lla r of
6 mm or less, Kohautia species can
be distinguished by a groove that is
present on all four sides of the stem.
The la m in a o f K. g r a n d iflo ra is
50-70 mm long and 3-5 mm wide,
w h ile th a t o f K. senegalensis is
n a rro w e r and sh o rte r (30-50
X 2-3 mm).
O ldenlandia species have a square
winged stem. O. herbacea differs
from O. corym bosa by its h ig h ly
branched, totally glabrous stem and
its spherical tufted habit.
Spermacoce octodon (Hepper) Lebrun & Stork Borreria octodon Hepper
Borreria meigei Assémien
Borreria setosa (Hiern) K. Schumann
Borreria setosum Hiern
Octodon setosum Hiern
Spermacoce ocymoides Burman f.
lam ina shape
The 14 species can be separated into
two categories on the basis of lamina
shape (Figure 1), i.e. those w ith a
lin e a r la m in a and those w ith an
oblong to elliptical lamina.
Borreria ocymoides (Burman f.) DC.
Borreria ramisparsa DC.
Borreria setidens Moq.
Spermacoce ramisparsa (DC.) Hiern
Spermacoce roxburghiana W all.
Spermacoce stricta Schlecht.
Tardavel ocymoides (Burman f.) Hiern
Spermacoce radiata (DC.) Sieber ex Hiern
Borreria radiata DC.
Spermacoce ruelliae DC.
Borreria articularis (L.f.) FN W illiams
Borreria hispida (L.) Schumacher
Borreria ruelliae (DC.) Schumann ex H. Thoms
Borreria scabra (Schumacher & Thonning) K. Schumann
Diodia scabra Schumacher & Thonning
Spermacoce hispida L.f.
Spermacoce stachydea DC.
Borreria stachydea (DC.) Hutchinson & Dalziel
Spermacoce leucada Hotchstetter ex Hiern.
Borreria leucada (Hotchstetter ex Hiern.) K. Schumann
Spermacoce verticillata L.
Borreria verticillata (L.) G. Meyer
Spermacoce globosa Schumacher &Thonning
Size of stipule segment is the next
trait to consider in species w ith a
sheath of more than 6 mm. In the two
species with teeth that are markedly
longer than the base of the sheath,
S. radiata can be readily identified by
its cartilaginous white margin, while
that of 5. octodon is scabrous.
Stem shape should be assessed if the
sheath is the same size as the teeth.
5. stachydea has a pubescent stem
w i t h r o u n d e d a n g le s , w h i l e
S. ruelliea has winged angles and
sparser pubescence.
Agriculture et développement ■
Special issue - M ay 1997
O
Oí
Agriculture et développement ■ Special issue - May 1997
1 to 3
3 mm
1 to 3
3 mm
10-15
slender
1-3 mm
3 to 5
1-2 mm
1 to 3
2-3 mm
5 to 7
slender
2-4 mm
7 to 10
5-12 mm
10 to 15
slender
8-11 mm
10 to 15
6-10 mm
12 to 16
5-7 mm
7 to 10
3-5 mm
5 to 7
3-4 mm
3-5 mm
3-5 mm
3-6 mm
4-8 mm
3-6 mm
5-9 mm
pubescent
7-15 mm
13-18 mm
pubescent
7-10 mm
8-13 mm
pubescent
10-14 mm
6-10 mm
pubescent
6-8 mm
glabrous with
toothed base
glabrous w ith
toothed base
scabrous
scabrous and
cartilaginous
scabrous
scabrous
scabrous
scabrous
scabrous
white and
cartilaginous
scabrous
scabrous
scabrous
glabrous
glabrous
glabrous*
pubescent
or scabrous
pubescent
glabrous*
glabrous*
glabrous*
scabrous
scabrous
glabrous*
scabrous
scabrous
glabrous
linear-lanceolate
30-90 x 7-20 mm
linear-lanceolate
30-50 x 5-10 mm
glabrous*
glabrous*
glabrous
glabrous
variable from
glabrous
to scabrous
variable
glabrous*
pubescent
or scabrous
pubescent
slightly
scabrous
glabrous
glabrous
linear
30-50 x2-3 mm
linear
50-70 x 1-2 mm
elliptical-lanceolate
30-60 x 7-15 mm
linear-lanceolate
20-40 x 1-4 mm
linear
15-40 x 1-2 mm
elliptical-lanceolate
30-70 x 4-15 mm
oblong-lanceolate
50-80 x 20-30 mm
linear
50-80 x 3-5 mm
oblong-elliptical
1 5 -3 0 x 5 -1 2 mm
linear
30-60 mm
linear-lanceolate
30-90 x 5-16 mm
opposite
decussate
opposite
opposite
decussate
opposite
decussate
opposite
opposite
decussate
opposite
decussate
opposite
opposite
opposite
opposite
opposite
opposite in
pseudo-whorls
glabrous
glabrous
pubescent
scabrous angles
smooth sides
glabrous
scabrous angles
smooth sides
pubescent
slightly
pubescent
glabrous angle
slightly
scabrous
hispid
pubescent
pubescent
square
grooved on
each side
square
grooved on
each side
square with
rounded angles
square, winged
square, winged
square
square, winged
square with
rounded angles
square, winged
round
finely striated
square, winged
square with
rounded angles
variable
Kohautia
senegalensis
Kohautia
grandiflora
Mitracarpus
villosus
O ldenlandia
corymbosa
O ldenlandia
herbacea
Spermacoce
chaetocephala
Spermacoce
latifolia
Spermacoce
octodon
Spermacoce
ocymoides
Spermacoce
radiata
Spermacoce
ruelliae
Spermacoce
stachydea
Spermacoce
verticillata
* The under surface of the leaves is glabrous except around the veins.
glabrous to
glabrate
pubescent
pubescent
scabrous
oblong-lanceolate
30-60 X 10-25 m m
opposite
scabrous angles
smooth sides
square, winged
Diodia
sarmentosa
5 to 7
2-3 mm
8 to 10
slender
5-7 mm
7-10 mm
scabrous
Stipulary sheath
Stipule
segment
Phyllotaxis
Margin
Under
surface
Upper
surface
Size
Lamina
Shape
and size
Pubescence
Stem
Shape
Species
Tableau 2. Characteristics o f Rubiaceae species o f western and central Africa.
Rubiaceae
Rubiaceae
Species descriptions are given to
enable the user to confirm the identi­
fication of species with similar vege­
tative structures.
ñ
M itracarpus vitiosus
fil
Spermacoce chaetocephala
U\
R
Species
descriptions
S/Hirmacoce ocymoidcs
Spermacoce la iifo lia
i-l'"-1
D iodia sarmentosa
All are herbaceous species, generally
with a square stem. The leaves are
entire and opposite, and the median
veins on the u p p e r surface are
depressed. They are sessile to subsessile, and the lamina base terminates
with a dentate stipulary sheath. The
white flowers, pink- and sometimes
blue-tinged, are arranged in axillary
or terminal inflorescences and rarely
solitary. The entire leaf margins are
scabrous or partially scabrous.
Spermacoce verticillata
a
Kohautia senegalensis
Kohautia grandiflora
SS
Oldenlandia coymbosa
Oldenlandia herbacea
Spermacocc radiata
Diodia sarmentosa Swartz
Spcrmacoce octodon
C a rtila g in o u s w h ite maiRin
Spermacoce stachydea
Scabrous maiyçin
Spermacoce ruelliae
Figure 1. Identification key for Rubiaceae species.
stipular sheath is fine (3-5 mm) and
tipped w ith 1-3 teeth (3 mm) each
side of the leaf base.
Kohautia Cham. &
Schlecht.
Although both species may be reco­
gnized by the size o f the lam ina,
identification is easier if the plants
are flowering.
D. sarm entosa is a weed of forest
regions w ith a creeping branched
habit. The slender stem is square and
w in g e d , and o n ly the angles are
pubescent. The oblong-lanceolate
lamina (30-60 x 10-25 mm) is sca­
brous above and pubescent under­
neath. The stipular sheath (7-10 mm
high) is tipped with several pointed
teeth (5-7 mm long).
K. g randiflora
K. g ra n d iflo ra a n d K. senegalensis
D. sarmentosa is similar to S. latifo­
lia, but the latter species has a pubes­
cent stem, while only the stem angles
of D. sarmentosa are pubescent.
are upright (up to 90 cm tall). All
sides o f th e ir square stems are
grooved from top to bottom . The
leaves are linear and glabrous. The
K. grandiflora has red to pink flowers
a ris in g fro m a sh o rt p e d ic e l
(1-2 mm). The corolla has an oval
lobe. The corymbiform inflorescence
is compressed. The fruit is a sessile
globular capsule. From a vegetative
viewpoint, the stem of K. grandiflora
can be s lig h tly scabrous at the
angles, w ith a linear lamina of 5070 mm x 35 mm.
A griculture et développement ■
Special issue - M a y 1997
Rubiaceae
Similar species
Although Kohautia species are simi­
lar to S p e r m a c o c e o c t o d o n and
S. radiata in appearance (linear leaf,
upright habit), th e ir short stipular
sheath w ith 1-3 teeth distinguishes
them fro m the tw o S p e r m a c o c e
s p e c ie s , w h i c h h a ve m u l t i p l e
pointed dentation sheaths.
Mitrocorpus villosus
w ith tw o loculi, each containing a
seed. The small, w hite flowers are
arranged in axillary glomerules.
This species is common throughout
intertropical Africa, and could have
been first introduced from the West
Indies during the 19th century.
O ldenlandia corymboso
Linn.
(Swartz) DC.
Kohautia grandiflora.
Photo H. M erlier
K. senegalensis
K. senegalensis has single w hite to
deep-pink flowers, arising from a 210 mm long pedicel. They are arran­
ged in a diffuse inflorescence. The
corolla has a linear lobe. The fruit is
a g lo b u la r pendunculate capsule.
The linear lamina (30-50 x 2-3 mm)
is narrower and shorter than that of
K. grandiflora.
O ldenlandia corymbosa.
Photo T. Le Bourgeois
M itracarpus villosus.
Photo T. Le Bourgeois
M . v illo s u s is ch a ra cte rize d by a
Kohautia senegalensis.
Photo T. Le Bourgeois
A griculture et développem ent ■
square pubescent stem with rounded
angles. The e llip tic a l la n ce o la te
leaves (30-60 x 7-15 mm), with short
petioles, have a lamina that is always
glabrous underneath, but only slight­
ly scabrous, pubescent or glabrous
above. M. villosus can also be reco­
gnized by its fruit, i.e. a pyxidium
Special issue - M a y 1 9 9 7
O. c o ry m b o s a has a sem i-upright
habit (20-40 cm) and grows in slight­
ly branched, diffuse tufts. The square
slender stem is finely winged, with
scabrous angles. The linear-lanceolate leaves (2040 x 1-4 mm) are
connected to a stipular sheath tipped
w ith 3-5 teeth. The lamina is dark
green, slightly pubescent and can be
somewhat scabrous above, while it is
pale green and glabrous underneath.
The flo w e rs fo rm p a u c iflo ro u s
corymbs of 2-5 w hite flowers. The
fru it is an oval dehiscent capsule
w ith tw o lo c u li c o n ta in in g m any
seeds.
white flowers are sessile and grou­
ped in dense glomerules o f about
2 cm.
This species is generally encountered
on degraded sandy soils or as a ruderal species. It is present in all hot
regions of the world.
Oldenlandia herbacea
(Linn.) Roxb.
Spermacoce chaetocephala.
S. chaetocephala could be confused
with species with a linear lamina, but
the lateral leaf veins are marked and
protrude underneath.
O. herbacea has an upright tufted
habit (7-60 cm). The winged square
stem is glabrous and h ighly bran­
ched. The leaves are linear (15-40 x
1-2 mm) and glabrous. The stipular
collar is short (26 mm) with 1-3 tee­
th. The flowers are generally solitary.
The fruit is a round bilocular capsule
containing many smooth brownish
seeds.
There are tw o varieties of this spe­
cies, according to the Flora of West
Tropical Africa (HUTCF1INSON et
a l., 1958): S. c h a e to c e p h a la var.
chaetocephala, w ith a robust stem
and a 4-15 mm lamina, and S. chae­
tocephala var. minor, with a slender
stem and a lamina that is never wider
than 4 mm.
stipular sheath (7-15 mm) is tipped
w ith pointed teeth that are longer
than the base of the sheath.
This weed, w h ich originates from
South America, flourishes in forest
regions.
Spermacoce octodon
(Hepper) Lebrun & Stork
Spermacoce latifolia
Aublet
It is possible to distinguish the two
species by their habit. O. herbacea is
upright and grows in compact tufts,
w h ile O. c o r y m b o s a has a se m i­
u p right habit, and a slender stem
w ith relatively little branching. In
addition, O. corymbosa flowers are
grouped while those of O. herbacea
are generally solitary.
Spermacoce
chaetocephala DC.
S. chaetocephala is an upright plant
that can grow up to 60 cm high. The
stem is square and glabrous with sca­
brous angles. The linear e llip tic a l
leaves (30-70 x 4-15 mm) are pubes­
cent to scabrous. The stipular sheath
is p u b e sce n t, tip p e d w ith sharp
2-4 mm teeth (5-7). The many small
Photo T. Le Bourgeois
5. la tifo lia can be identified by its
blue-tinged flowers, grouped in den­
se a x illa ry glom erules, and by its
creeping habit. It has a winged, squa­
re, pubescent stem, with roots some­
times growing from the nodes. The
p u b e s c e n t leaves are o b lo n g lanceolate (50-80 x 20-30 mm). The
S. octo d o n is a savanna weed with
an u p rig h t ha b it (20-50 cm). The
leaves are linear (50-80 x 3- 5 mm),
slightly scabrous above and glabrous
underneath. A narrow, lightly pubes­
cent stipular sheath extends from the
leaf base. The sheath (13-18 mm) has
many very fine teeth that are marked­
ly longer (8-11 mm) than the base.
The white flowers are arranged in a
terminal glomerule.
The s tip u la r sheath distinguishes
5. o c to d o n from Kohautia species,
i.e. K o ha utia plants have a sheath
with only 2-3 teeth, and all sides of
their stems are grooved.
A griculture et développement ■
Special issue - M a y 1997
59
Rubiaceae
Spermacoce ocymoides
Burmann f.
Spermacoce ruelliae.
Photo M . Déat
5. ocym oides has a slender square
stem w ith w in g e d and scabrous
angles. The leaves are oblong ellipti­
cal (15-30 x 5-12 mm), pale green
and g la b ro u s. The short s tip u la r
sheath (5 mm) has 5-7 small teeth.
There are many small white to pink
flowers that grow in non-spherical
glomerules.
Spermacoce ocymoides.
Photo H. M erlier
Spermacoce radiata
5. ruelliae grows abundantly In crop­
fields of savanna regions. It has a
square winged stem w ith scattered
hairs. The leaves are linear-lanceolate (30-90 x 5-16 mm) and scabrous,
and paler underneath as compared
to the upper surface. The stipular
sheath (10-14 mm) has 12-16 teeth
(5-7 mm). The white flowers are sup­
ported by fine leaf bracts and form
terminal and axillary glomerules. It is
common throughout tropical Africa
and prefers clay soils.
It is quite similar to S. stachydea, but
can be distinguished by its stem shape.
Sieber ex Hiern
Spermacoce stachydea
DC.
S. r a d ia ta Is ch a ra c te riz e d by its
Spermacoce radiata.
white cartilaginous leaf margins and
its pubescent stipular sheath w ith
many teeth that are markedly longer
than the base. The pub e sce n t to
hispid stem is round and somewhat
reddish in c o lo u r . The la m in a
is linear (30-60 x 4-6 mm) and gla­
brous. The many small white flowers
are sessile and fo rm te rm in a l or
sub-terminal glomerules.
Photo H, M erlier
Spermacoce ruelliae DC.
This species is q u ite co m m o n in
degraded ferruginous soils of savan­
na regions.
A griculture et développement ■
Special issue - M a y 19 97
S. stachydea has an upright habit,
and can grow up to 60 cm high. The
square pubescent stem has rounded
angles. The leaves have a linear lan­
ceolate and densely scabrous lamina
(30-90 x 7-20 mm). They have a
short indistinct petiole, extended by
a broad pubescent stipular sheath.
Rubiaceae
stipular sheath has 5-7 teeth. The
white flowers form small, dense axil­
lary glomerules. This ruderal species
flourishes in Sudano-Cuinean clima­
tic zones.
BRUNEL J.-F., HIEPKO P., SCHOLZ H.,
1 9 8 4 . F lo re a n a ly t iq u e du T o g o . G TZ ,
Eschborn, Germany, p. 398-437.
CARRIERE R.,1994. Plantes de Guinée à
l'u s a g e des é le v e u rs et des v é té rin a ir e s .
CIRAD-EMVT, Montpellier, France, 167 p.
DEAT M., 1981. Principales adventives du
cotonnier en Afrique de l'Ouest. Description
et t e c h n iq u e s de lu tte . C IR A D -IR C T ,
Montpellier, France, p. 82-84.
FOURNET J., 1978. Flore illu strée des
p h a n é ro g a m e s de G u a d e lo u p e et de
M a rtin iq u e . INRA, Paris, France, p. 1 1551 220.
FOURNET J., HAM M ERTON J.-L., 1991.
Weeds of the lesser Antilles. Mauvaises herbes
des p e tites A n tille s . IN R A, Paris, France,
p. 136-138.
GARCIA J.G.L., MACBRYDE B„ M OLINA
A . R., H E R R E R A -M A C B R Y D E O ., 1 9 7 5 .
M aleza s p revalentes de A m e ric a C e n tra l.
I n t e r n a t io n a l P la n t P r o te c tio n C e n te r,
El Salvador, San Salvador, p. 127-128.
Spermacoce stachydea.
Photo T. Le Bourgeois
HEYW OOD V.FH., 1978. Flowering plants
of the world. Oxford University Press, Oxford
London, Melbourne, p. 257-259.
The sheath has many teeth that are
ciliated at the apex. The flowers are
arranged in false capitulae mixed
with leaves.
H U T C H I N S O N J., D A L Z IE L J .M .,
HEPPER F.N., 1958. Flora of West Tropical
Africa, vol II, second Edition. The Whitefriars
Press (é d .), L o n d o n and T o n b r id g e ,
UK, 544 p.
S. stachydea and S. ruelliae are mor­
Spermacoce verticillata.
phologically quite similar, but can be
d istin g u is h e d by th e ir stems and
leaves. S. s ta c h y d e a has a round
stem, more pubescent that that of
S. ruelliae, which is square with w in ­
ged angles. The leaves of S. stachy­
dea are more scabrous than those of
S. ruelliae and have a short petiole.
In addition, the sheath teeth of S. sta­
chydea are ciliated at the apex.
Photo M . Déat
Spermococe verticillata L.
IVENS G.W., M O O D Y K, EGUNJUB J.K.,
1978. West African weeds. Oxford University
Press, Ibadan, Nigeria, p. 172-174.
LE BOURGEOIS T., MERLIER H „ 1995.
Adventrop. Les adventices d'Afrique soudanosahélienne. CIRAD-CA, Montpellier, France,
640 p.
LECO NTE
H .,
HUMBERT
H.,
G A G N E P A IN F., 1 922. Flore gé n éra le de
l'Indochine, vol III. MASSET et Cie (Eds), Paris,
France, p. 146-147, p. 441 -442.
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Agriculture et développement 8 : 43-50.
A griculture et développement ■
Special issue - M a y 1997
Rubiaceae
Abstract... Résumé... Resumen
J. SALAMERO, P. MARNOTTE, T. LE BOURGEOIS,
J. SALAMERO, P. MARNOTTE, T. LE BOURGEOIS,
J. SALAMERO, P. MARNOTTE, T. LE BOURGEOIS,
A. CARRARA — Practical identification key for
A. CARRARA — Détermination pratique de
A. CARRARA — Determinación práctica de
14 Rubiaceae weed species of western and
14 rubiacées, adventices d'Afrique de l'Ouest
14 rubiáceas adventicias del Africa occidental
central Africa.
et du Centre.
y central.
Some weeds of the Rubiaceae family have been identified
Des ad ventices de la fa m ille des rubiacées ont été
Se han id en tific a d o ad v entic ias de la f a m ilia de la
in western and central Africa. An identification key was
identifiées en Afrique de l'Ouest et du Centre. Une clé de
rubiáceas en Africa occidental y central. Una clave de
developed using eight plant structure characters. A table
d é te rm in a tio n com prend 8 caractères de l'a p p a re il
ide n tific a c ió n in clu y e ocho cara cte res del a p a ra to
of these criteria and description of how to use the key are
végétatif. Le tableau de ces critères, la démarche de la clé
vegetativo. Se presentan el cuadro de dichos criterios y el
presented, without full plant descriptions.
sont présentés, sans f a ir e appel à une description
procedimiento de la clave sin recurrir a una descripción
complète des plantes.
completa de las plantas.
M o ts -clé s : m a u v a is e h e rb e , Rubiaceae, Diodia
Palabras clave : maleza, Rubiaceae, Diodia sarmentosa,
sarmentosa, Kohautia grandiflora, Kohautia senegalensis,
Mitracarpus villosus, Oldenlandia corymbosa, Oldenlandia
herbacea, Spermacoce chaetocephala, Spermacoce
latifolia, Spermacoce octodon, Spermacoce ocymoides,
Spermacoce radiata, Spermacoce ruelliae, Spermacoce
stachydea, Spermacoce verticillata, id e n tific a tio n ,
Kohautia grandiflora, Kohautia senegalensis, Mitracarpus
villosus, Oldenlandia corymbosa, Oldenlandia herbacea,
Spermacoce chaetocephala, Spermacoce la tifo lia ,
Spermacoce octodon, Spermacoce ocymoides, Spermacoce
radiata, Spermacoce ruelliae, Spermacoce stachydea,
Sperm acoce v ertic illa ta, id e n tific a c ió n , a p a r a t o
appareil végétatif, Afrique.
vegetativo, Africa.
K e yw ords : w e e d , R u b ia c e a e , D oidia sarm entosa,
Kohautia grandiflora, Kohautia senegalensis, Mitracarpus
villosus, Oldenlandia corymbosa, Oldenlandia herbacea,
Spermacoce chaetocephala, Spermacoce la tifo lia ,
Spermacoce octodon, Spermacoce ocymoides, Spermacoce
radiata, Spermacoce ruelliae, Spermacoce stachydea,
Spermacoce verticillata, identification, plant structure,
Africa.
A griculture et développem ent ■
Special issue - M a y 1997