BLUMEA 22 (1975) 541—553 A synopsis of the African and Madagascan Rubiaceae — Naucleeae C.E. Ridsdale in collaboration with R.C. Bakhuizen+van+den+Brink+Jr Naucleeae The centre of distribution of the is Malesia and Asia, there are but a few African and The revision of the for Flora Malesiana Madagascan representatives. group of entailed an extensive nomenclatural evaluation and typification the genera (Bakhuizen Brink This taxonomic van den Jr., 1970). has been followed by detailed investigations and re-evaluation of the tribal and limits. The conceived a generic Naucleeae, as by K. Schumann (1891), have mostly been considered a highly natural group (Verdcourt, 1958) raised has and have even been to family status (Airy Shaw, 1973). Bremekamp (1966) the Naucleeae. been the only botanist ever to question the homogeneous nature of after re-examinationof of of all and However, materials most representatives genera sections of genera one could only come to a conclusion similar to Bremekamp’s. The is of only character that die genera of the tribe have in common the arrangement the tribes. The inflorescence in a spherical head, a feature recurring independently in many genera Mitragyna and Uncaria are here placed together in a subtribe Mitragyninae and the transferred into transferred to tribe Cinchoneae; Cephalanthus is a separate tribe, a move first suggested by Bremekamp (1966). These groups will be treated separately in to The as far be form a somewhat papers shortly appear. remaining genera, as can judged, homogeneous tribe. The last world-wide revision of the group was by Haviland (1897), who, considering the available the extensive detailed of the and material at time, provides an survey group of the problems involved. The work of Merrill (1915), who attempted to clarify the situationin Nauclea and Neonauclea, has created greatconfusion, particularly in typification Brink It the attention from (Bakhuizen van den Jr., 1970). also served to draw away many of the of the of the Adina s.l. All authors problems group, particularly genus subsequent the have accepted Merrill's interpretation without critically re-examining group on a has world-wide basis. The availability of more extensive recent collections considerably added to of the but at the has increased the of our knowledge group same time problems generic distinction. In the taxonomic studies on the Malesian genera it became clear that either the would have be modified or that generic concepts, as presently recognized, to should A all taxa be returned to one highly variable genus. rapid glance at the synonymy faced with the will show that previous experienced workers have also been same problem. Thus the old generic concepts have been re-modeled. The generic limits of the Malesian and Asiatic genera have been revised and, as a con- it became that also the African and sequence, apparent certain changes were necessary in Madagascan taxa. The isolated nature ofAditta microcephala is no new discovery, being previously emphasized by Baillon (1879) and Haviland (1897). Two of the new Madagas- Neonauclea can genera were recently published (Capuron, 1972) as I'S, although one was some time ago placed by Homolle under manuscript names in Adina. B. A. 1. Krukoff botanist of Malesian Botany, Rijksherbarium, Leiden. 2. Rijksherbarium, Leiden. 542 BLUMEA VOL. 22, No. 3, 1975 It is ancient considered that the Naucleeae are a relatively group, with closest affinity to tribe The inflorescences be the Cinchoneae. are highly modified and may viewed as and all is condensed or reduced, they are very similar. However, there strong evidence to that the is of each with few is suggest group composed many genera a species, as accepted for some well-defined genera e.g. Burttdavya (monotypic), Anthocephalus (2 species), Nauclea (4 African, ±5 Malesian species). The diversity of the stipules of the vegetative the apices, nature of the reduced or modified organs on the node of the flowering axis, the and placentation, are all constant in the well-delimited genera. In the remaining little-studied these features variable. genera are highly Thus, within Adina s.l., the diversity and within the than between other of the Naucleeae. variation genus is greater genera It has been concluded (Ridsdale & Bakhuizen van den Brink Jr., unpublished data) such that genera are unnatural heterogeneous assemblages of taxa which cannot readily have drawn be accomodated elsewhere. Thus, new, more acceptable generic limits been for all of is taxa the tribe. This synopsis of the African and Madagascan genera intended as the first of the Naucleeae. The and will interlock hi a series papers on keys descriptions of with those to be published in a revision the Asiatic and Malesian representatives. In this full synopsis descriptions and other details are not included: for Continental Africa these are available in the local the will be treated in readily floras, Madagascan genera shortly Professor first full by J. F. Leroy, the preliminary note being in the press (Leroy, 1975). LITERATURE AIRY H. K. In C. A SHAW, 1973. J. Willis, dictionary of floweringplants and ferns, ed. 8: 779. Observation BAILLON, H. 1879. sur les Naucleees. Adansonia 12: 311 —316. BAKHUIZEN BRINK R. Nomenclature and of the of Rubiaceae- VAN DEN Jr., C. 1970. typification genera Naucleeae and a proposal to conserve the generic name Nauclea L. Taxon 19: 468—480. BBNTHAM, G., & J. D. HOOKER, 1876. Genera Plantarum 2: 29—32. BREMEKAMP, C. E. B. 1966. Remarks on the position, the delimitation and the subdivision ofthe Rubiaceae. Acta Bot. Neerl. 15: 1 —33. R. Contribution l'etude de la flore forestiere de deux nouvelles CAPURON, 1972. a Madagascar: sur especes du genre Neonauclea Merr. (Rubiaceae). Adansonia II, 12: 303 —386. — Sur 1973- l'idcntite du Cephalanthus chinensis Lam. Adansonia II, 13: 471 —743. HALIJ, N. 1966. Flore du Gabon 12, 1 : 25—53. G. D. A revision the Bot. HAVILAND, 1897. of tribe Naucleeae. J. Linn. Soc. 33: 1 —94, pi. 1 —4. Flora of West ed. vol. HUTCHINSON, J., &J. M. DALZIEL, 1963. Tropical Africa, 2, 2: 161—164. F. Note LEROY, J. 1975. preliminaire sur les Rubiacees-Nauclees Malgaches. Adansonia II, 14: 681—685. the of MERRILL, E. D. 1915. On application the generic name Nauclea of Linnaeus. J. Wash. Acad. Sc. 5: 530—542. E. Les Naucleeae PETIT, 1958. (Rubiaceae) du Congo Beige et du Ruanda-Urundi. 2. Mitragyna et Nauclea. Bull. Bot. Brux. Jard. 28: 1—13. K. In SCHUMANN, 1891. Rubiaceae. Engler & Prantl, Die natiirlichen Pflanzenfamilien, ed. 1, 4, 4: 55—60. VERDCOURT, B. 1958. Remarks on the classification of the Rubiaceae. Bull. Jard. Bot. Brux. 28:209—281. PRESENTATION OF DATA axis In many Rubiaceae differentiated shoot systems occur, the main being orthotropic and the lateral These branches axes plagiotropic. plagiotrop'c may obligatory produce vegetative branches or may, under the influence offlowering factors, produce a flowering reduced axis bearing leaves, stipules, and inflorescences, or only develop a solitary in- florescence. Different authors have used a rather variable terminology to describe this situation. It is considered that the inflorescence is, in principle, always terminal, either terminal die on orthotropic and plagiotropic shoots, or terminal on the plagiotropic branch and terminal short lateral branches of the on plagiotropic shoot. Where such a C. E. Ridsdale: African and Madagascan Rubiaceae-Nauckeae 543 short shoot is unbranched and bears a solitary inflorescence head, the stalk has generally short be termed 'peduncle'. Here this is considered to be a shoot with one or two nodes, the stalk above the uppermost node being termed the 'true peduncle', and that below being the 'flowering axis'. In the descriptions such inflorescences are termed 'lateral' for convenience. It is considered that a flowering plagiotropic shoot may bear reduced leaves at the various nodes; the stipules or more rarely stipules and leaves ofthe node subtending be small and reduced or sometimes be modified into the inflorescence may simply may The small foliaceous bracts which surround the young inflorescence. receptacle may bear filamentous to spathulate 'interfloral bracteoles' between the flowers. All these different organs have, at varying times, been called bracts. KEY TO THE GENERA OF THE NAUCLEEAE SENSU K. SCHUMANN The if attached in the Ia. two placentas variously attached to the septum; upper third, then either Y-shaped with 2 short ascending arms and a long descending foot, or the then either a small, short, obovoid boss; if medianly attached to septum discoidal bilobed and with central attachment, or oblong to slightly unbranched; placentas pallid in colour; ovules and seeds ofeach placenta either (predominantly) pendulous, imbricate the whole of or spreading in all directions, never upwardly along length the placenta. Fruitlets either free on the receptacle and then the endocarp splitting from bottom to and ovaries and fruitlets top, or loosely cohering indehiscent, or lobes imbricate and Malesia also fused into a (pseudo-)syncarp. Corolla (in Asia valvate) 3 b. attached the The two placentas adnate to the septum, or in upper third, long and pendulous, thick, dark brown to black; ovules and seeds of each placenta upwardly imbricate along the whole placenta. Fruitlets free on the receptacle, endocarp of fruit splitting from top to bottom. Corolla lobes valvate. tribe Cinchoneae: subtribe Mitragyninae 2 2a. Climbers, short flowering axes modified into hooks, seeds alate, long tailed, one tail deeply bipartite Uncaria b. Trees, short flowering axes not modified into hooks; seeds alate, not long tailed, one tail sometimes shallowly notched Mitragyna arillus. 3a. Ovules solitary, funiculus with a well-developed tribe Cephalantheae: Cephalanthus natalensis b. absent. Ovules solitary to numerous, arillus tribe Naucleeae s.s 4 Ovaries and fruitlets connate into 4a. persistently a syncarp 5 b. Ovaries and fruitlets free 8 clavate and? 6 5a.