The African Species of Landolphia P. Beauv. Series of Revisions Of
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WAGENINGEN AGRICULTURAL UNIVERSITY PAPERS 92-2(1992 ) TheAfrica n specieso f Landolphia P. Beauv. Series ofrevision s of Apocynaceae XXXIV by J.G.M.Persoon , F.J.H.va nDilst ,R.P . Kuijpers, A.J.M. Leeuwenberg and G.J.A.Von k Departmentof Plant Taxonomy Wageningen,Agricultural University, TheNetherlands Dateo fpublicatio n 24-9-1992 Wageningen By Agricultural University Contents Abstract 1 Introduction 1 Generalpar t 2 Geographicaldistributio n 2 Habit and growth 3 Relationship toothe rgener a ; 4 Keyt oth egener ao fLandolphiina e 5 Taxonomicpar t 6 Thegenu sLandolphi a 6 Sectionalarrangemen t 7 Discussion onth erelationshi p ofth esection san d their delimitation 10 Keyt oth especie s 11 TheAfrica n species 16 Hybrid 205 Nominanuda 206 Excluded species 206 Acknowledgement 209 Indexo fexsiccata e 209 Index ofscientifi c names 228 Abstract LandolphiaP .Beauv. ,a n apocynaceous genusdistinc t bycoroll a tubeusuall y thickened above the anthers, glabrous fruits and mostly dense inflorescences, hasbee n revised for mainland Africa. Thegenu s nowcount s 50specie s on that continent.I ti sconfine d towe tan dseasonall ydr yAfric a andMadagascar ,wher e 10-13endemi c species are found. Five new names and four new combinations were necessary: for three new species and the two other new names and the four newcombination sfo r speciesformerl y housedi nAnthoclitandra an dApha- nostylis,gener a reduced to synonyms of Landolphia here. The latter two new names are for species of which the epithets were otherwise occupied. Relation ships to the nearest genera are discussed. Keys are given to identify specimens to the genera in Landolphiinae, now counting 9 genera, and to the species in Landolphia. Illustrations add to the extended descriptions, and maps present the distribution of the species. Vernacular names, often numerous ones for widely distributed species, were gleaned from herbarium labels and literature. Landolphiaspp .produc elatex ,use dfo r rubber and bird lime. Thefruit s ofmos t speciesar eedible . Introduction Thepresen tpublicatio n isa monographi crevisio no fth eContinental African specieso fLandolphia, allo fwhic h areconfine d to thearea . Thestud y ismainl y based on the examination ofherbariu m material.I n addition, the authors have hadth eopportunit y ofobservin glivin gplant si nthei rnatura l habitat belonging to 33 ofth e5 0specie smaintaine d here. It has been possible to trace almost all the type specimens of the names and synonymsdiscusse d inth epresen t revision. Theauthorshi pi sshare d asfollows : J.G.M. Persoon: Introductory paragraphs (in cooperation with A.J.M. Leeuwenberg),specie s 1-13,15-20,22-26,28-34,36,38,42-50an dinde xo fexsic - catae. F.J.H.va nDilst :specie s 37. R.P.Kuijpers : species 14,21,27, 35,3 9an d 41. G.J.A.Vonk :specie s40 . Since Pichon (1953) monographed the genus, many more collections have been made, and some new species have been discovered, especially in Gabon. After Kuijpers had monographed Anthoclitandra and Aphanostylis again, Per soon concluded that both genera should beunite d with Landolphia. Therefore the latter author is responsible for the new combinations and the new name needed for the purpose. Vonk discovered that Landolphia reticulata was erro neously placed in Ancylobotrys by Pichon, as he had the opportunity to study thefirs t flowers and fruits evercollecte d ofthi sspecies . WageningenAgric. Univ. Papers92-2 (1992) 1 General part Geographical distribution The genus Landolphia is represented in Continental Africa with 50 species. Theremainin g 10-13 speciesar eendemi ci n Madagascar. L. owariensisi sth emos twidesprea d amongthem ,a si ti sknow n from almost all tropical African countries (hence the formidable synonymy). Almost the sameare ai soccupie d byL. incerta. Thethir d largest areai n sizei stha t covered by L. buchananii in Central and East Africa. The fourth and fifth places are occupiedb yL. kirkiian dL. parvifolia respectively .L. kirkiieve nreache s South Africa.L.foretiana cover sa nare afro m Guineet oZaire .L. landolphioides occur s from Nigeria and Sao Tome eastwards to Sudan and Uganda. Several species arefoun d from Nigeriat oZaire ;thes ear eL. robustior, L. mannii, L. congolensis, L. dewevrei, L.glabra and L. violacea. L. ligustrifolia and L. villosa occur from Cameroun to Zaire.L. camptoloba isknow n from Zaire, Angola and Zambia, L. tholloniian dL. lanceolatafro m Congo,Zair ean d Angola,an d thelas t rather widely distributed Central Africa species is L. rufescensknow n from Zaire, Angolaan dnorther n Zambia. Somespecie shav ebee ncollecte dmainl yi nWes tAfrica ,L. dulcis fro m Senegal to Angola and L. hirsuta from Senegal to Cameroun. Several species remain westo fth eDahome yGap :L. heudelotii, L. micrantha,L. membranacea,L. mac- rantha and L. nitidula. The last occupies the smallest area among them, it is confined to coastal Guinee and Sierra Leone.Tw o species occur on both sides of the Dahomey Gap, but are restricted to West Africa: L. calabrica known from Sierra Leone to Nigeria and L. togolana from Cote d'lvoire to Nigeria. Quite a few species are only known from in and around Gabon: L. uniflora, L. subrepanda, L. stenogyna, L. maxima,L. letestui, L. glandulosa, L. bruneelii, L.jumellei, L. lecomtei, L.ferrea and L. breviloba. Four specieshav e been col lectedonl yi nGabon ,L. noctiflora, L.pyramidata, L.axillaris an d L.reticulata. Afe wmor especie scove rsmal lareas :L.flavidiflora i nCameroun ,L. gossweileri in southern Angola and L. cuneifolia approximately where Angola, Zaire and Zambia meet. Two specieshav e an eastern distribution: L. eminiana is mainly found in eastern Zaire to Tanzania, and L. watsoniana occurs along the coast from Kenya to Mozambique. The three locations of L. angustisepala, are as far apart as Gabon and in the east of Zaire, which may either indicate, that thisspecie si sstil lt ob ediscovere di nbetween ,o rtha ti tma ywide nth eindividua l variationwithi nth ever yclosel yallie dL. parvifolia. It is interesting, that sometimes related species tend to vicariance, e.g. the threeL. hirsuta, L. jumellei an dL. villosa, i nwestern ,centra lan deaster n Central Africa respectively. Their areas slightly overlap, as is the case with L.dulcis and L. congolensisi nwester nan dcentra lAfrica . Theclosel y allied and geogra phicallyseparat eL. togolanaan dL. letestuiappea rt ob etru evicariants . The small areas of distribution known from Landolphia species cover more 2 WageningenAgric. Univ.Papers 92-2 (1992) or less the refugia shown on figure one of Jean Maley (1989). L.macrantha may have originated in the West African refugium on the border of Guinee and Liberia,whil eth e other twofores t species,L. membranaceaan d L. micran- tha,ma yhav esurvive dthere .Fiv eo fMaley' srefugi a nearth ecoas tfro m Camer- oun to Congo are candidates for having protected the eleven species known from Gabon adjacent areas. L. noctiflora,L. pyramidata,L. axillarisan d L. reticulata probably found a shelter in the refugium in southern Gabon. Asw e are stilldiscoverin g speciesne wt o sciencean d newlocalitie sfo r known species thelatte rremark sremai n speculative. Reference Maley, J. 1989. Late quaterny climatic changes in the African rain forest: forest refugia and the major role of sea surface temperature. In: M. Leinen & M.Sarnthei n (eds.),Paleoclimatolog y andPaleometereology :Moder n and Past Patterns ofGloba lAtmospheri c Transport, p.585-616 .Kluwe rAcademi cPub lishers, Dordrecht/Boston/London. Habit and growth Most Landolphia species are large lianas with large curled terminal tendrils. One of thetw o axillary branches forms the continuation of theplan t rendering its growth sympodial. The two axillary buds side by side of the tendril open simultaneously, soon afterwards one of the two branches grows more slowly and stopsafte r havingproduce d severallea fpair so rafte r havingbranche d once and often having produced some inflorescences. The other branch shapes the next apical tendril after producing some leaf pairs and the process is repeated. Therefore these plants grow in the model of Koriba (Halle &Oldeman , 1970). They sharethi smode lwit h almost all other specieso fth e subtribesLandolphii- naean d Willughbeiinaeo fth e Carisseae. Onlya fe w speciesar eknow n asrhizomatou s pyrophytic shrubs insavannas . Theyar eprobabl y descendantso flianescen t species,e.g .th erhizomatou s shrub L. thollonii is closely allied to the large liana L. parvifolia, of which species it even was a variety in Pichon's revision (1953).I n several other families woody plants alsoma ysurviv eth eyearl ybus hfir e asrhizomatou s shrubswhic h flower on first-year shoots. In several species lianas or trees may survive annual bush firea s geopyrophytic rhizomatous shrubs. These shrubs bear leaves similar to those of sucker shoots of the fully developed plants (e.g.th e climberStrychnos gossweilerian dth etree sS. pungens an d S.spinosa). WageningenAgric. Univ. Papers92-2 (1992) Relationshipt oothe rgener a As can be deduced from the detailed description of the Landolphiinae the genera are all closely allied to each other by almost all characters. Therefore theirdelimitatio n hasbee ndispute du pt o thepresen t day.Picho n did anexcel lentjo b defining the eleven genera he has distinguished and nine of which are maintainedhere .Si xo fthe mhav ebee nrevise dagai nrecently .Afte r comparison ofal lspecie so fth eLandolphiinae Persoo nha sconcluded ,tha tonl yAnthoclitan- draan d Aphanostylis are not distinguishable from Landolphia as Pichon indi cated.Th ebasa lpar to fth episti lhea d(clavuncul acf . Pichon),i nfac t thestigma , hassimila rshape si nAnthoclitandra an dsevera lspecie so fLandolphia. Relativel y long anthers in short corolla tubes, represent the only remaining character to separateAphanostylis from Landolphia, as Pichon indicated, but the speciesh e kepti nAphanostylis are sodifferen t from each other, that they are placed here intw odifferen t subgenera ofLandolphia.