Rhopalobrachium is an endemic New Caledonian genus of Rubiaceae with controversial tribal positio... more Rhopalobrachium is an endemic New Caledonian genus of Rubiaceae with controversial tribal position, because its protologue was apparently based on two distantly related species, Rhopalobrachium fragrans and Rhopalobrachium congestum. Despite its new circumscription as a monotypic genus (Rhopalobrachium fragrans) the tribal placement of Rhopalobrachium remained unknown. We investigated, for Rhopalobrachium fragrans, all morphological characters currently used for circumscribing tribes in the subfamily Ixoroideae sensu lato. The species has axillary inflorescences, with valvate flower aestivation, drupaceous fruits with a single pendulous ovule per locule, and 3-pororate pollen grains. We also performed Bayesian and parsimony analyses based on two chloroplast markers, rps16 intron and trnT-F region, to assess the phylogenetic position of Rhopalobrachium within Ixoroideae sensu lato. These analyses produced well-resolved and strongly supported topologies. The results of both the morphological survey and phylogenetic analyses indicated a position of Rhopalobrachium fragrans in the tribe Vanguerieae and a close relationship with the Pacific genus Cyclophyllum.
A new species of Paederia L. (Rubiaceae, Rubioideae, Paederieae), P. ntiti Mouly & Puff, endemic ... more A new species of Paederia L. (Rubiaceae, Rubioideae, Paederieae), P. ntiti Mouly & Puff, endemic to the Comoros (Grande Comore, Anjouan and Mayotte) and occurring in natural elevated forests is described and illustrated. Its conservation status is evaluated and the species is rated ‘Endangered’ (EN). A key to the Paederia taxa of the Comorian archipelago is provided. Also included are notes on the three other species of rubiaceous climbers and lianas known from the Comoros: Paederia bojeriana (A. Rich. ex DC.) Drake Danais comorensis Drake, and Uncaria africana G. Don.
New generic circumscriptions of the Paleotropical tribe Vanguerieae in the subfamily Ixoroideae s... more New generic circumscriptions of the Paleotropical tribe Vanguerieae in the subfamily Ixoroideae s.l. (Rubiaceae) have recently been established as a result of a series of phylogenetic studies conducted by Lantz and Bremer. The genus Canthium Lam. was shown in their study to be highly polyphyletic, and a largely dioecious group was for the first time identified within Vanguerieae. The dioecious group sensu Lantz and Bremer comprises about 140 species classified in eight genera: Canthium (Canthium subg. Bullockia Bridson), Dinocanthium Bremek., Leroya Cavaco, Neoleroya Cavaco, Peponidium (Baill.) Arènes, Pseudopeponidium Homolles ex Arènes, Pyrostria Comm. ex Juss., and Scyphochlamys Balf. f. We sequenced 79 Vanguerieae taxa and performed phylogenetic analyses based on sequence data from two nuclear (ETS and ITS) markers to: (1) pinpoint the phylogenetic positions of the Comorean and Indian Ocean Canthium and the Southeast Asian Canthium confertum Korth. group in Vanguerieae; (2) evaluate the phylogenetic utility of three taxonomic characters (bract type, locule number, and fruit shape) previously and currently used for delimiting genera in the dioecious group; and assess the evolution of functional dioecy in Vanguerieae. The results support a further disintegration of Canthium s.l., as the Comorean and Malagasy Canthium species are shown for the first time to be closely related to Peponidium. Similarly, C. confertum appears to have a close affinity with Cyclophyllum Hook. f. The combined analyses show that the dioecious group can be subdivided into four morphologically distinct clades formally recognized as genera: Bullockia (Bridson) Razafim., Lantz & B. Bremer, here elevated from Canthium subgen. Bullockia Bridson, as well as Cyclophyllum, Peponidium (including all Comorean, Malagasy, and Seychellean Canthium species), and Pyrostria (including Dinocanthium, Leroya, Neoleroya, Pseudopeponidium, and Scyphochlamys). All described species of Canthium subgen. Bullockia are transferred to Bullockia: B. dyscriton (Bullock) Razafim., Lantz & B. Bremer, B. fadenii (Bridson) Razafim., Lantz & B. Bremer, B. impressinervia (Bridson) Razafim., Lantz & B. Bremer, B. mombazensis (Baill.) Razafim., Lantz & B. Bremer, B. pseudosetiflora (Bridson) Razafim., Lantz & B. Bremer, and B. setiflora (Hiern) Razafim., Lantz & B.
The little known Rubiaceae genus Villaria is endemic mostly to the coastal forests of the Philipp... more The little known Rubiaceae genus Villaria is endemic mostly to the coastal forests of the Philippines. Traditionally, it has been placed in the tribe Gardenieae. Later it was transferred to Octotropideae sensu Robbrecht and Puff. Villaria was placed among the “primitive” genera of the tribe, which are essentially characterized by large fruits, horizontal ovules and numerous seeds. Parsimony and Bayesian analyses of the combined plastid (rps16 and trnT-F) dataset strongly support the inclusion of Villaria in Octotropideae as well as monophyly of the genus. However, our molecular results do not conform to the current informal groups of the tribe delimited by fruit size, ovule position, number of seeds and exotesta thickenings. Instead, a close relationship between Villaria and two “central genera” (Hypobathrum and Pouchetia) is revealed for the first time. This clade is sister to a group comprising “primitive” (Fernelia), “advanced” (Kraussia and Polysphaeria) and “central” (Feretia) representatives. In addition, our combined tree strongly supports a sister taxa relationship between Canephora and Paragenipa. Villaria is characterized by unilocular ovaries, parietal placentation and strictly horizontal ovules. These features are unique within the Octotropideae. We recognize a total of five Villaria species, one new species (V. leytensis) is described here, and two species (V. philippinensis and V. rolfei) are transferred into synonymy with V. odorata. Each species is fully described, and a key to the species, a distribution map and illustrations are provided.
Deux espèces nouvelles de Th iollierea (Rubiaceae) endémiques de Nouvelle-Calédonie sont décrites... more Deux espèces nouvelles de Th iollierea (Rubiaceae) endémiques de Nouvelle-Calédonie sont décrites et illustrées. Une clé de détermination des espèces du genre Th iollierea est donnée. Th iollierea rigaultii sp. nov. et T. dagostinii sp. nov. appartiennent au groupe des espèces à fl eurs blanches et violacées. Th iollierea rigaultii sp. nov. possède des caractères uniques pour ce groupe : infl orescences unifl ores, face interne du calice totalement recouverte par des cérocystes, corolle coriace et de grande taille. Th iollierea dagostinii sp. nov. est caractérisée par une combinaison inédite de caractères : face interne des stipules entièrement recouverte par des cérocystes, hypanthe subailé, tube du calice entier sans division secondaire, pilosité du fi let hirsute et lâche, à disposition cylindrique. Les deux espèces sont endémiques du massif ultramafi que du Boulinda, situé sur la côte nord-ouest de la Grande Terre, et plus précisément, pour chacune, d'une petite région paraforestière sur sols hypermagnésiens conférant à la fl ore locale des taux élevés de microendémisme. L'état actuel des populations des deux espèces et l'examen des menaces qui pèsent sur elles permettent de proposer un statut UICN correspondant à la catégorie « en danger critique d'extinction » (CR).
ABSTRACT À partir d'une analyse bibliographique, les auteurs étudient la composition,... more ABSTRACT À partir d'une analyse bibliographique, les auteurs étudient la composition, l'organisation et le rôle de la biodiversité des prairies permanentes en fonction de leur régime d'exploitation.Une première partie décrit la diversité des prairies, du paysage aux espèces. Une seconde est centrée sur les fonctions écologiques assurées par cette biodiversité. Enfin les divers services écosystémiques que celle-ci rend sont analysés.Une synthèse souligne qu'en tenant compte des contraintes pédo-climatiques, des régimes de fauche, de pâturage et de fertilisation trop intensifs pourraient compromettre la résilience des prairies et leurs fonctions écologiques. En revanche, une exploitation modérée favorise une meilleure résistance aux aléas climatiques et la séquestration du carbone.
Greeniopsis Merr. is a small genus of Rubiaceae endemic to the Philippines. Previously, no molecu... more Greeniopsis Merr. is a small genus of Rubiaceae endemic to the Philippines. Previously, no molecular data have been available for Greeniopsis and its taxonomic position has remained controversial. Based on morphology, the genus was tentatively included in the tribe Aleisanthieae (Ixoroideae) along with the Southeast Asian genera Aleisanthia and Aleisanthiopsis. To determine the taxonomic position of Greeniopsis and evaluate the monophyly of the genus, sequences of the rps16 and trnT-F regions of cpDNA of all seven Greeniopsis species were generated. Parsimony and Bayesian analyses of the combined plastid dataset strongly support the inclusion of Greeniopsis in Aleisanthieae as well as its monophyly. Woolly hairs on the abaxial leaf surface occur in only one Greeniopsis species and can no longer be regarded a synapomorphy of the tribe. The generic status of Aleisanthia, Aleisanthiopsis, and Greeniopsis is maintained. A revision of Greeniopsis, including a key to species, descriptions, distribution maps, and illustrations, is provided.
The tribe Alberteae, presently classified in the subfamily Ixoroideae (Rubiaceae), has historical... more The tribe Alberteae, presently classified in the subfamily Ixoroideae (Rubiaceae), has historically been an artificial grouping of genera. In the present study, phylogenetic analyses of the chloroplast DNA markers rbcL, ndhF, trnS-G, trnT-F and trnH-psbA as well as the ITS region of the nuclear ribosomal DNA, are done to assess the delimitation of Alberteae. The resulting phylogenetic hypothesis is highly resolved, with most clades strongly supported. The genus Alberta is found to be paraphyletic as presently circumscribed. As a consequence, we propose the new genus Razafimandimbisonia Kainul. & B. Bremer to accommodate the Malagasy species. The newly delimited Alberta is distinguished by having two calycophylls that expand after anthesis as well as awl-shaped stigma lobes. Razafimandimbisonia is distinguished from the remaining Alberteae by having dehiscent fruits and anthers without basal appendages. We demonstrate that the genera Airosperma, Boholia and Crossopteryx are not associated with Alberteae, as has previously been suggested. Alberteae is considered restricted to the genus Alberta endemic to Southeast Africa, and the two Malagasy endemic genera Nematostylis and Razafimandimbisonia. Rubiaceae ples for DNA restriction endonuclease analysis. Taxon 36: 715-722. Hall, T.A. 1999. BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/ NT. Nucleic Acids Symp. Ser. 41: 95-98.
Th ree new species of the tribe Vanguerieae (Rubiaceae) from Madagascar are described with illust... more Th ree new species of the tribe Vanguerieae (Rubiaceae) from Madagascar are described with illustrations. Two species are placed in Pyrostria, one in Peponidium. Peponidium crassifolium is recognized by its thick and slightly succulent leaves, Pyrostria pendula by the pendulous fl owers and persistent pedicels, and Pyrostria serpentina by a serpentine habit and small leaves. Th e morphology and taxonomic history of the dioecious genera of the tribe are discussed.
Rhopalobrachium is an endemic New Caledonian genus of Rubiaceae with controversial tribal positio... more Rhopalobrachium is an endemic New Caledonian genus of Rubiaceae with controversial tribal position, because its protologue was apparently based on two distantly related species, Rhopalobrachium fragrans and Rhopalobrachium congestum. Despite its new circumscription as a monotypic genus (Rhopalobrachium fragrans) the tribal placement of Rhopalobrachium remained unknown. We investigated, for Rhopalobrachium fragrans, all morphological characters currently used for circumscribing tribes in the subfamily Ixoroideae sensu lato. The species has axillary inflorescences, with valvate flower aestivation, drupaceous fruits with a single pendulous ovule per locule, and 3-pororate pollen grains. We also performed Bayesian and parsimony analyses based on two chloroplast markers, rps16 intron and trnT-F region, to assess the phylogenetic position of Rhopalobrachium within Ixoroideae sensu lato. These analyses produced well-resolved and strongly supported topologies. The results of both the morphological survey and phylogenetic analyses indicated a position of Rhopalobrachium fragrans in the tribe Vanguerieae and a close relationship with the Pacific genus Cyclophyllum.
We performed phylogenetic analyses of DNA sequences of three chloroplast markers: rbcL, rps16, an... more We performed phylogenetic analyses of DNA sequences of three chloroplast markers: rbcL, rps16, and trnT-F, to rigorously test the monophyly of competing circumscriptions of the tribe Ixoreae. Several genera traditionally or currently associated with the type genus Ixora L. were included in the analyses. Ixora as currently circumscribed appears paraphyletic, as many other genera are nested within it with strong support: Captaincookia N. Hallé, Doricera Verdc., Hitoa Nadeaud, Myonima Comm. ex Juss., Sideroxyloides Jacq., Thouarsiora Homolle ex Arènes, and Versteegia Valeton. Further, Aleisanthia Ridl., Aleisanthiopsis Tange, and Greenea Wight & Arn. are more closely related to Ixora and allies than the monotypic genus Scyphiphora C. F. Gaertn. Consequently, Ixoreae fide Andreasen and Bremer is not monophyletic without an exclusion of Scyphiphora. Ixoreae fide Robbrecht and Manen is not monophyletic unless Captaincookia and Doricera are included. The monophyly of a morphologically heterogeneous Ixoreae alliance consisting of Ixora and its relatives Aleisanthia, Aleisanthiopsis, and Greenea is, however, strongly supported. In order to recognize monophyletic and morphologically consistent groups, we adopt a narrow circumscription of Ixoreae (including Bemsetia Raf., Captaincookia, Charpentiera Vieill., Doricera, Hitoa, Ixora, Myonima, Pancheria Montrouz., Sideroxyloides, Thouarsiora, Tsiangia But, H. H. Hsue & P. T. Li, and Versteegia), and two new tribes are erected for Aleisanthia + Aleisanthiopsis and Greenea, respectively. The Indo-Malesian Aleisanthieae and the pantropical Ixoreae s. str. are sister groups, and the Southeast Asian Greeneeae is sister to the Ixoreae-Aleisanthieae clade.
Rhopalobrachium is an endemic New Caledonian genus of Rubiaceae with controversial tribal positio... more Rhopalobrachium is an endemic New Caledonian genus of Rubiaceae with controversial tribal position, because its protologue was apparently based on two distantly related species, Rhopalobrachium fragrans and Rhopalobrachium congestum. Despite its new circumscription as a monotypic genus (Rhopalobrachium fragrans) the tribal placement of Rhopalobrachium remained unknown. We investigated, for Rhopalobrachium fragrans, all morphological characters currently used for circumscribing tribes in the subfamily Ixoroideae sensu lato. The species has axillary inflorescences, with valvate flower aestivation, drupaceous fruits with a single pendulous ovule per locule, and 3-pororate pollen grains. We also performed Bayesian and parsimony analyses based on two chloroplast markers, rps16 intron and trnT-F region, to assess the phylogenetic position of Rhopalobrachium within Ixoroideae sensu lato. These analyses produced well-resolved and strongly supported topologies. The results of both the morphological survey and phylogenetic analyses indicated a position of Rhopalobrachium fragrans in the tribe Vanguerieae and a close relationship with the Pacific genus Cyclophyllum.
A new species of Paederia L. (Rubiaceae, Rubioideae, Paederieae), P. ntiti Mouly & Puff, endemic ... more A new species of Paederia L. (Rubiaceae, Rubioideae, Paederieae), P. ntiti Mouly & Puff, endemic to the Comoros (Grande Comore, Anjouan and Mayotte) and occurring in natural elevated forests is described and illustrated. Its conservation status is evaluated and the species is rated ‘Endangered’ (EN). A key to the Paederia taxa of the Comorian archipelago is provided. Also included are notes on the three other species of rubiaceous climbers and lianas known from the Comoros: Paederia bojeriana (A. Rich. ex DC.) Drake Danais comorensis Drake, and Uncaria africana G. Don.
New generic circumscriptions of the Paleotropical tribe Vanguerieae in the subfamily Ixoroideae s... more New generic circumscriptions of the Paleotropical tribe Vanguerieae in the subfamily Ixoroideae s.l. (Rubiaceae) have recently been established as a result of a series of phylogenetic studies conducted by Lantz and Bremer. The genus Canthium Lam. was shown in their study to be highly polyphyletic, and a largely dioecious group was for the first time identified within Vanguerieae. The dioecious group sensu Lantz and Bremer comprises about 140 species classified in eight genera: Canthium (Canthium subg. Bullockia Bridson), Dinocanthium Bremek., Leroya Cavaco, Neoleroya Cavaco, Peponidium (Baill.) Arènes, Pseudopeponidium Homolles ex Arènes, Pyrostria Comm. ex Juss., and Scyphochlamys Balf. f. We sequenced 79 Vanguerieae taxa and performed phylogenetic analyses based on sequence data from two nuclear (ETS and ITS) markers to: (1) pinpoint the phylogenetic positions of the Comorean and Indian Ocean Canthium and the Southeast Asian Canthium confertum Korth. group in Vanguerieae; (2) evaluate the phylogenetic utility of three taxonomic characters (bract type, locule number, and fruit shape) previously and currently used for delimiting genera in the dioecious group; and assess the evolution of functional dioecy in Vanguerieae. The results support a further disintegration of Canthium s.l., as the Comorean and Malagasy Canthium species are shown for the first time to be closely related to Peponidium. Similarly, C. confertum appears to have a close affinity with Cyclophyllum Hook. f. The combined analyses show that the dioecious group can be subdivided into four morphologically distinct clades formally recognized as genera: Bullockia (Bridson) Razafim., Lantz & B. Bremer, here elevated from Canthium subgen. Bullockia Bridson, as well as Cyclophyllum, Peponidium (including all Comorean, Malagasy, and Seychellean Canthium species), and Pyrostria (including Dinocanthium, Leroya, Neoleroya, Pseudopeponidium, and Scyphochlamys). All described species of Canthium subgen. Bullockia are transferred to Bullockia: B. dyscriton (Bullock) Razafim., Lantz & B. Bremer, B. fadenii (Bridson) Razafim., Lantz & B. Bremer, B. impressinervia (Bridson) Razafim., Lantz & B. Bremer, B. mombazensis (Baill.) Razafim., Lantz & B. Bremer, B. pseudosetiflora (Bridson) Razafim., Lantz & B. Bremer, and B. setiflora (Hiern) Razafim., Lantz & B.
The little known Rubiaceae genus Villaria is endemic mostly to the coastal forests of the Philipp... more The little known Rubiaceae genus Villaria is endemic mostly to the coastal forests of the Philippines. Traditionally, it has been placed in the tribe Gardenieae. Later it was transferred to Octotropideae sensu Robbrecht and Puff. Villaria was placed among the “primitive” genera of the tribe, which are essentially characterized by large fruits, horizontal ovules and numerous seeds. Parsimony and Bayesian analyses of the combined plastid (rps16 and trnT-F) dataset strongly support the inclusion of Villaria in Octotropideae as well as monophyly of the genus. However, our molecular results do not conform to the current informal groups of the tribe delimited by fruit size, ovule position, number of seeds and exotesta thickenings. Instead, a close relationship between Villaria and two “central genera” (Hypobathrum and Pouchetia) is revealed for the first time. This clade is sister to a group comprising “primitive” (Fernelia), “advanced” (Kraussia and Polysphaeria) and “central” (Feretia) representatives. In addition, our combined tree strongly supports a sister taxa relationship between Canephora and Paragenipa. Villaria is characterized by unilocular ovaries, parietal placentation and strictly horizontal ovules. These features are unique within the Octotropideae. We recognize a total of five Villaria species, one new species (V. leytensis) is described here, and two species (V. philippinensis and V. rolfei) are transferred into synonymy with V. odorata. Each species is fully described, and a key to the species, a distribution map and illustrations are provided.
Deux espèces nouvelles de Th iollierea (Rubiaceae) endémiques de Nouvelle-Calédonie sont décrites... more Deux espèces nouvelles de Th iollierea (Rubiaceae) endémiques de Nouvelle-Calédonie sont décrites et illustrées. Une clé de détermination des espèces du genre Th iollierea est donnée. Th iollierea rigaultii sp. nov. et T. dagostinii sp. nov. appartiennent au groupe des espèces à fl eurs blanches et violacées. Th iollierea rigaultii sp. nov. possède des caractères uniques pour ce groupe : infl orescences unifl ores, face interne du calice totalement recouverte par des cérocystes, corolle coriace et de grande taille. Th iollierea dagostinii sp. nov. est caractérisée par une combinaison inédite de caractères : face interne des stipules entièrement recouverte par des cérocystes, hypanthe subailé, tube du calice entier sans division secondaire, pilosité du fi let hirsute et lâche, à disposition cylindrique. Les deux espèces sont endémiques du massif ultramafi que du Boulinda, situé sur la côte nord-ouest de la Grande Terre, et plus précisément, pour chacune, d'une petite région paraforestière sur sols hypermagnésiens conférant à la fl ore locale des taux élevés de microendémisme. L'état actuel des populations des deux espèces et l'examen des menaces qui pèsent sur elles permettent de proposer un statut UICN correspondant à la catégorie « en danger critique d'extinction » (CR).
ABSTRACT À partir d'une analyse bibliographique, les auteurs étudient la composition,... more ABSTRACT À partir d'une analyse bibliographique, les auteurs étudient la composition, l'organisation et le rôle de la biodiversité des prairies permanentes en fonction de leur régime d'exploitation.Une première partie décrit la diversité des prairies, du paysage aux espèces. Une seconde est centrée sur les fonctions écologiques assurées par cette biodiversité. Enfin les divers services écosystémiques que celle-ci rend sont analysés.Une synthèse souligne qu'en tenant compte des contraintes pédo-climatiques, des régimes de fauche, de pâturage et de fertilisation trop intensifs pourraient compromettre la résilience des prairies et leurs fonctions écologiques. En revanche, une exploitation modérée favorise une meilleure résistance aux aléas climatiques et la séquestration du carbone.
Greeniopsis Merr. is a small genus of Rubiaceae endemic to the Philippines. Previously, no molecu... more Greeniopsis Merr. is a small genus of Rubiaceae endemic to the Philippines. Previously, no molecular data have been available for Greeniopsis and its taxonomic position has remained controversial. Based on morphology, the genus was tentatively included in the tribe Aleisanthieae (Ixoroideae) along with the Southeast Asian genera Aleisanthia and Aleisanthiopsis. To determine the taxonomic position of Greeniopsis and evaluate the monophyly of the genus, sequences of the rps16 and trnT-F regions of cpDNA of all seven Greeniopsis species were generated. Parsimony and Bayesian analyses of the combined plastid dataset strongly support the inclusion of Greeniopsis in Aleisanthieae as well as its monophyly. Woolly hairs on the abaxial leaf surface occur in only one Greeniopsis species and can no longer be regarded a synapomorphy of the tribe. The generic status of Aleisanthia, Aleisanthiopsis, and Greeniopsis is maintained. A revision of Greeniopsis, including a key to species, descriptions, distribution maps, and illustrations, is provided.
The tribe Alberteae, presently classified in the subfamily Ixoroideae (Rubiaceae), has historical... more The tribe Alberteae, presently classified in the subfamily Ixoroideae (Rubiaceae), has historically been an artificial grouping of genera. In the present study, phylogenetic analyses of the chloroplast DNA markers rbcL, ndhF, trnS-G, trnT-F and trnH-psbA as well as the ITS region of the nuclear ribosomal DNA, are done to assess the delimitation of Alberteae. The resulting phylogenetic hypothesis is highly resolved, with most clades strongly supported. The genus Alberta is found to be paraphyletic as presently circumscribed. As a consequence, we propose the new genus Razafimandimbisonia Kainul. & B. Bremer to accommodate the Malagasy species. The newly delimited Alberta is distinguished by having two calycophylls that expand after anthesis as well as awl-shaped stigma lobes. Razafimandimbisonia is distinguished from the remaining Alberteae by having dehiscent fruits and anthers without basal appendages. We demonstrate that the genera Airosperma, Boholia and Crossopteryx are not associated with Alberteae, as has previously been suggested. Alberteae is considered restricted to the genus Alberta endemic to Southeast Africa, and the two Malagasy endemic genera Nematostylis and Razafimandimbisonia. Rubiaceae ples for DNA restriction endonuclease analysis. Taxon 36: 715-722. Hall, T.A. 1999. BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/ NT. Nucleic Acids Symp. Ser. 41: 95-98.
Th ree new species of the tribe Vanguerieae (Rubiaceae) from Madagascar are described with illust... more Th ree new species of the tribe Vanguerieae (Rubiaceae) from Madagascar are described with illustrations. Two species are placed in Pyrostria, one in Peponidium. Peponidium crassifolium is recognized by its thick and slightly succulent leaves, Pyrostria pendula by the pendulous fl owers and persistent pedicels, and Pyrostria serpentina by a serpentine habit and small leaves. Th e morphology and taxonomic history of the dioecious genera of the tribe are discussed.
Rhopalobrachium is an endemic New Caledonian genus of Rubiaceae with controversial tribal positio... more Rhopalobrachium is an endemic New Caledonian genus of Rubiaceae with controversial tribal position, because its protologue was apparently based on two distantly related species, Rhopalobrachium fragrans and Rhopalobrachium congestum. Despite its new circumscription as a monotypic genus (Rhopalobrachium fragrans) the tribal placement of Rhopalobrachium remained unknown. We investigated, for Rhopalobrachium fragrans, all morphological characters currently used for circumscribing tribes in the subfamily Ixoroideae sensu lato. The species has axillary inflorescences, with valvate flower aestivation, drupaceous fruits with a single pendulous ovule per locule, and 3-pororate pollen grains. We also performed Bayesian and parsimony analyses based on two chloroplast markers, rps16 intron and trnT-F region, to assess the phylogenetic position of Rhopalobrachium within Ixoroideae sensu lato. These analyses produced well-resolved and strongly supported topologies. The results of both the morphological survey and phylogenetic analyses indicated a position of Rhopalobrachium fragrans in the tribe Vanguerieae and a close relationship with the Pacific genus Cyclophyllum.
We performed phylogenetic analyses of DNA sequences of three chloroplast markers: rbcL, rps16, an... more We performed phylogenetic analyses of DNA sequences of three chloroplast markers: rbcL, rps16, and trnT-F, to rigorously test the monophyly of competing circumscriptions of the tribe Ixoreae. Several genera traditionally or currently associated with the type genus Ixora L. were included in the analyses. Ixora as currently circumscribed appears paraphyletic, as many other genera are nested within it with strong support: Captaincookia N. Hallé, Doricera Verdc., Hitoa Nadeaud, Myonima Comm. ex Juss., Sideroxyloides Jacq., Thouarsiora Homolle ex Arènes, and Versteegia Valeton. Further, Aleisanthia Ridl., Aleisanthiopsis Tange, and Greenea Wight & Arn. are more closely related to Ixora and allies than the monotypic genus Scyphiphora C. F. Gaertn. Consequently, Ixoreae fide Andreasen and Bremer is not monophyletic without an exclusion of Scyphiphora. Ixoreae fide Robbrecht and Manen is not monophyletic unless Captaincookia and Doricera are included. The monophyly of a morphologically heterogeneous Ixoreae alliance consisting of Ixora and its relatives Aleisanthia, Aleisanthiopsis, and Greenea is, however, strongly supported. In order to recognize monophyletic and morphologically consistent groups, we adopt a narrow circumscription of Ixoreae (including Bemsetia Raf., Captaincookia, Charpentiera Vieill., Doricera, Hitoa, Ixora, Myonima, Pancheria Montrouz., Sideroxyloides, Thouarsiora, Tsiangia But, H. H. Hsue & P. T. Li, and Versteegia), and two new tribes are erected for Aleisanthia + Aleisanthiopsis and Greenea, respectively. The Indo-Malesian Aleisanthieae and the pantropical Ixoreae s. str. are sister groups, and the Southeast Asian Greeneeae is sister to the Ixoreae-Aleisanthieae clade.
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Papers by Arnaud Mouly