for 14 Rubiaceae weed species of western and - Agritrop
Transcription
for 14 Rubiaceae weed species of western and - Agritrop
for 14 Rubiaceae weed species of western and central Africa. 1 » . t,C- ,a jC j TP: ¿ y w ..... .. ....... ...............— „ , _ 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. Bibliography A K O N B U N D U I.O ., A G Y A K W A C .W ., 1987. A han db o o k o f West A frica n weeds. IITA, O yo Road, PMB 5320, Ibadan, Nigeria, p. 366-377 BACKER C.A., 1973. Atlas of 220 weeds o f s u g a r-c a n e fie ld s in Java. G r e s h o ff's Rum phius Fund, Amsterdam, Netherlands, p. 649-677. BAYER A.G., 1992 . Im portant Crops of the W o r ld and th e ir Weeds (S cientific and Common Names, Synonyms and WSSAAVSSJ. A p p r o v e d C o m p u te r C odes). 2 e e d it io n , BAYER (Ed.), L e ve rk u s s e n , G e rm a n y , 1 465 p. B E R H A U T J., 1 9 6 7 . Flore du Sénégal. Clairafrique éditeur, D a k a r, Senegal, 485 p. 5. verticillata can be identified by its leaves, which are arranged in pseudo-whorls, and by its highly bran ched and upright habit. The leaves are lin e a r-la n c e o la te (30-50 x 510 mm) and glabrous. The short fine BOSSER )., C A D E T T ., G U E H O J., MARAIS W., 1989. Flore des Mascareignes, la R é u n io n , M a u r ic e , R o drigues. The Sugar I n d u s tr y R esearch I n s titu te , M a u r it iu s , ORSTOM, Paris, The Royal Botanic Gardens, Kew, UK, p. 1-62. BOUDET G ., LEBRUN J.-P., DEMANGE R., 1986. Catalogue des plantes vasculaires du M ali. CIRAD-IEMVT, MaisonAlfort, France, p. 238-245. MERLIER H ., 1 9 9 4 . A c t u a lis a t io n de quelques synonymies (3e édition). CIRAD-CA, Montpellier, France, 145 p. MERLIER H ., M O N T E G U T J., 1 9 8 2 . A d ve n tice s T ropicales. O RSTO M , CIRAD GERDAT, ENSH, Montpellier, France, 490 p. OGUNYEMI S., M O O D Y K., 1972. Some Weeds at IITA. IITA, Ibadan, Nigeria, 57 p. PEYRE DE FABREGUES B„ LEBRUN J.-P., 1976. Catalogue des plantes vasculaires du Niger. CIRAD-IEMVT, M o n tp e llie r, France, p. 238-243. SOERJANI M., KOSTERMANS A.J.G.H., TIJTROSOEPOMO G., 1987. Weeds of rice in In d o n e s ia . B a la i p u sta ka . Jakarta Pusat, Indonesia, p. 492-540. V E R N O N R., 1 9 8 3 . F ie ld g u id e to im p o rta n t arable weeds o f Z am bia. M o u n t M a k u lu C e n tra l, R esearch S ta tio n , Department of Agriculture, Chilanga, Zambia, p. 72. V IA R O U G E N ., M ARNOTTE P., MERLIER H., 1995. D éterm ination pratique des m a u v a is e s h e rb e s du g e n re S ida L. 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