Apocynaceae-Apocynoideae)
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THE NERIEAE (APOCYNACEAE-APOCYNOIDEAE) A. J. M. LEEUWENBERG1 ABSTRACT The genera of tribe Nerieae of Apocynaceae are surveyed here and the relationships of the tribe within the family are evaluated. Recent monographic work in the tribe enabled the author to update taxonomie approaches since Pichon (1950) made the last survey. Original observations on the pollen morphology ofth egener a by S.Nilsson ,Swedis h Natural History Museum, Stockholm, are appended to this paper. RÉSUMÉ L'auteur étudie lesgenre s de la tribu desNeriea e desApocynacée s et évalue lesrelation s del a tribu au sein de la famille. Un travail monographique récent sur la tribu a permit à l'auteur de mettre à jour lesapproche s taxonomiques depuis la dernière étude de Pichon (1950). Lesobservation s inédites par S. Nilsson du Muséum d'Histoire Naturelle Suédois à Stockholm sur la morphologie des pollens des genres sontjointe s à cet article. The Apocynaceae have long been divided into it to generic rank and in his arrangement includ two subfamilies, Plumerioideae and Apocynoi- ed Aganosma in the Echitinae. Further, because deae (Echitoideae). Pichon (1947) added a third, of its conspicuous resemblance to Beaumontia, the Cerberioideae, a segregate of Plumerioi it may well be that Amalocalyx (Echiteae— deae—a situation which I have provisionally ac Amalocalycinae, according to Pichon) ought to cepted. These subfamilies were in turn divided be moved to the Nerieae. into tribes and subtribes. Comparative studies Pichon's system is artificial, because he used have shown that the subdivision of the Plume the shape and the indumentum of the area where rioideae is much more natural than that of the the connectives cohere with the head of the pistil Apocynoideae. as the only character to distinguish the four tribes Although the Apocynoideae is a coherent of his Apocynoideae. That the Nerieae is the grouping, it has so far proved very difficult to most satisfactorily defined tribe of the Apocy devise a satisfactory and practicable subdivision noideae only becomes evident after combina for it. Pichon (1950 ) had little confidence in early tions of characters are taken into account. classifications ofth e subfamily, although, like his Pichon divided the Nerieae into nine subtribes predecessors, he seems to have preferred a more (Table 1), but it is certain that not all of these or less artificial treatment. He recognized four can be maintained. Indeed, it is questionable tribes in Apocynoideae —Echiteae, Nerieae, whether the Nerieae ought to be divided into Apocyneae, and Ichnocarpeae—each of which subtribes at all. was further divided into a number of subtribes. Connections canb e seenbetwee n certain groups However, none of these can be maintained as ofgenera . Thus Adenium has flowers that resem delimited by Pichon. For example, there appears ble those oiNerium, especially in the corona and tob ea greate r degreeo fsimilarit y between Echites in the long bristly appendages at the apices of and Rhodocalyx of the Echiteae and Mandevilla the anthers. and Mesechites of the Ichnocarpeae than is ev Wrightia, Pleioceras, and Stephanostema can ident from his classification. also be grouped together, as they have a corona Nevertheless, the Nerieae, dealt with in detail (deeply incised in the first two and almost entire here, are maintained largely as proposed by Pi in the last one), more or less bifurcate ramifi chon except for the following changes: Dewev- cation, and a similarly shaped corolla. There is, rella is transferred to Parsonsiineae (Echiteae). in addition, the resemblance shown by Beau Amphineurion is treated as a synonym of Aga- montia and Vallaris to Wrightia, in particular to nosma. De Candolle (1844 ) regarded Amphineu those ofit sspecie swit h abroa d corolla and thick- rion as a section ofAganosma, but Pichon raised walled fruits. Strophanthus, with comparable 1 Department of Plant Taxonomy, Agricultural University, Wageningen, The Netherlands. MONOGR. SYST. BOT. MISSOURI BOT. GARD. 25: 157-160. 1988. 158 1985AETFA TPROCEEDINGS-MODER N SYSTEMATIC STUDIES TABLE 1. Pichon's treatment of the Nerieae compared with the arrangement proposed here. Pichon(1950) Leeuwenberg (1988) Nerieae Nerieae 1. Neriinae (as Amphineuriinae) Adenium (5;Afr. , Arab.; Plaizier, 1980) Amphineurion (= Aganosmä) Nerium (1; Medit. to China; Leeuwenberg, 1984) Potisia Strophanthus (38;Afr. , As.; Beentje, 1982) Dewevrella (to Parsonsiinae) Wrightia(23 ; Afr., As.; Ngan, 1965) lsonema Pleioceras (5; Afr.; Barink, 1983) Nerium Stephanostema (1; Afr.; Barink, 1983) 2. Beaumontiinae Beaumontia (9;As. ; Rudjiman, 1986) Vallaris Vallaris (3;As. ; Rudjiman, 1982) Parabecumontia( = Vallaris) Vallariopsis (1; As.;Rudjiman , 1986) Muantum (= Beaumontia) Kibatalia(15 ;As. ; Rudjiman, 1986) Beaumontia Malouetia (ca. 15;Afr. , S.Amer. ;Va n der Ploeg, 1984, 1985; Fallen, 3. Strophantinae unpubl.) Christya( = Strophantus) Allowoodsonia (1; Pacif.; Fallen; unpubl.) Roupellina( = Strophantus) Funtumia (2;Afr. ; Zwetsloot, 1981) Strophanthus Mascarenhasia(ca . 10;Afr. , Mad.; Markgraf, 1976) Farquharia (1; Afr.; Zwetsloot, 1981) 4. Mascarenhasiinae Alafia(ca . 25;Afr. , Mad.; Pichon, 1954) Mascarenhasia lsonema (3; Afr.; Van der Ploeg, 1983) Echitella (= Mascarenhasia) Pottsia(3 ;As. ; Tsiang & Li, 1977) 5. Alafiinae Alafia Aladenia (= Farquharia) 6. Kibataliinae Funtumia Kibatalia 7. Wrightiinae Wrightia Wallida( = Wrightiä) Scleranthera( = Wrightia) Pleioceras Stephanostema 8. Malouetiinae Malouetia Malouetiella( = Malouetia) (Pichon, 1952) 9. Adeniinae Adenium Vallariopsis not included. Allowoodsonia not mentioned. fruits and flowers with a corona, also belongs these genera from each other. Within the group, here. Malouetia and Allowoodsonia are so close in all A third group comprises Kibatalia, Funtumia, their characters, including those of the seeds (the Mascarenhasia, Malouetia, and Allowoodsonia. only ones without a coma in the whole of the These five genera probably all conform to the Apocynoideae), that the two should probably be model of Koriba when in the flowering stage. united. Kibatalia differs from them only in the Funtumia, however, matches the model of Pré rostrum and coma of the seeds. vost in the juvenile stage. This has still to be Farquharia and Alafia, large lianes with cori investigated for the other four genera. The co aceous leaves, exhibit similarity in their flowers riaceous leaves,smal l stunted inflorescences, and and fruits, and they therefore form a fourth group fleshy corollas can make it difficult to distinguish within the Nerieae. LEEUWENBERG-NERIEAE 159 Of the three genera not yet mentioned, Val- XXXIV. Les Malouetiinae d'Afrique. Bull. Jard. lariopsis, Isonema, and Pottsia, it is mainly Val- Bot. État 22: 115-135. 1954. Classification des Apocynacées: lariopsis that shows connections with other gen XXXIX. Revision du Genre Alafia Thou. Bull. era. Thus, its flowers resemble those ofKibatalia, Jard. Bot. État 24: 129-222. Allowoodsonia, and Malouetia, and to a lesser PLAIZIER, A. C. 1980. A revision of Adenium Roem. extent those of Vallaris, Isonema, and Pottsia. & Schult, and of Diplorhynchus Welw. ex Fie. & Hiern (Apocynaceae). Meded. Landbouwhoge The four groups outlined above could, if nec school 80(12): 1-40. essary, be distinguished as the subtribes Neri- RUDJIMAN. 1982. A revision of Vallaris Burm. f. inae, Wrightiinae, Kibataliinae, and Alafiinae, (Apocynaceae). Meded. Landbouwhogeschool but they are difficult to define. 82(11): 1-17. Strophantus gratus has flowers reminiscent . 1986. A revision of Beaumontia Wall., Ki- batalia G. Don, and Vallariopsis Woods. (Apo of Adenium and Nerium in their corolla and co cynaceae). Agric. Univ. Wageningen Pap. 86(5): rona. The corona and syncarpous fruits of Neri 1-99. um have their counterparts in several Wrightia TSIANG, Y. & P. T. Li. 1977. Apocynaceae. In Flora species. The model of Leeuwenberg has been rec Republicae Popularis Sinicae 63:1-XH, 1-249. ognized in species of Nerium, Strophanthus boi- VAN DER PLOEG, J. 1983. A revision of Isonema R. Br. and Pycnobotrya Benth. (Apocynaceae). Med vinii, and Wrightia. The seeds of Beaumontia ed. Landbouwhogeschool 83(4): 1-20. resemble those of Isonema and Pottsia. In ad . 1984. Serieso frevision s ofApocynacea e XIV. dition, the flowers of Isonema bear lateral ap Notes on the African species of the genus Ma pendages on the corolla lobes and, in this respect, louetia A.DC. (Apocynaceae). Bull.Jard . Bot. État 54: 283-288. are like those of Mascarenhasia. The remarkable -. 1985. A revision of Cyclocotyla Stapf, Dew- long, slender, rostrate seeds of Strophanthus, with evrella De Wild., and the African species of Ma a coma on the rostrum, are also found in Fun- louetia A.DC. (Apocynaceae). Agric. Univ. Wa tumia and Kibatalia. On the other hand, the seeds geningen Pap. 85: 57-83. of Adenium and Farquharia have basal and api ZWETSLOOT, H. J. C. 1981. A revision of Farquharia Stapfand Funtumia Stapf (Apocynaceae). Meded. cal comas that are persistent, while in Strophan Landbouwhogeschool 81(16): 1-46. thus, Funtumia, and Isonema the second coma is deciduous. APPENDIX LITERATURE CITED POLLEN DESCRIPTION OF BARINK, M. M. 1983. Series of revisions of Apocy- APOCYNACEAE-APOCYNOIDEAE-NERIEAE2 naceae XII. A revision ofPleioceras Baill., Stepha- nostema K. Schum. and Schizozygia Baill. (Apo- Pollen grains usually spheroidal, 3(-4)-porate, ex cynaceae). Meded. Landbouwhogeschool 83(7): 21- ceptionally polypantoporate (Vallariopsis); exine 53. smooth, perforated,