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International audience; Aim. Climate warming reshuffles biological assemblages towards less cold-adapted but more warm-adapted species, a process coined thermophilization. However, the velocity at which this process is happening generally lags behind the velocity of climate change, generating a climatic debt the temporal dynamics of which remain misunderstood. Relying on high-resolution time series of vegetation data from a long-term monitoring network of permanent forest plots, we aim at quantifying the temporal dynamics – up to a yearly resolution – of the climatic debt in the understorey of temperate forests before identifying the key determinants that modulate it. Location. France. Time period. 1995–2017. Taxa studied. Vascular plants. Methods. We used the community temperature index (CTI) to produce a time series of understorey plant community thermophilization, which we subsequently compared to a time series of mean annual temperature changes over the same period and for the same sites. The direction and magnitude of the difference (i.e., the climatic debt) was finally analysed using linear mixed-effect models to assess the relative contributions of abiotic and biotic determinants, including forest stand characteristics. Results. We found a significant increase in CTI values over time (0.08–0.09 °C/decade), whereas the velocity of mean annual temperature changes was three times higher over the same period (0.22–0.28 °C/decade). Hence, the climatic debt increased over time and was greater in forest stands with higher basal area or older trees as well as under warmer macroclimate. By contrast, a greater frequency of anthropogenic disturbances decreased the climatic debt, while natural disturbances and herbivory had no impact. Conclusions. Although often overlooked in understanding the climatic debt of forest biodiversity, changes in forest stand characteristics may modulate the climatic debt by locally modifying microclimatic conditions. Notably, the buffering effect of the upper canopy layer implies microclimate dynamics that may provide more time for understorey plant communities to locally adapt.

In Rubiaceae phylogenetics, the number of markers often proved a limitation with authors failing to provide well-supported trees at tribal and generic levels. A robust phylogeny is a prerequisite to study the evolutionary patterns of traits at different taxonomic levels. Advances in next-generation sequencing technologies have revolutionized biology by providing, at reduced cost, huge amounts of data for an increased number of species. Due to their highly conserved structure, generally recombination-free, and mostly uniparental inheritance, chloroplast DNA sequences have long been used as choice markers for plant phylogeny reconstruction. The main objectives of this study are: 1) to gain insight in chloroplast genome evolution in the Rubiaceae (Ixoroideae) through efficient methodology for de novo assembly of plastid genomes; and, 2) to test the efficiency of mining SNPs in the nuclear genome of Ixoroideae based on the use of a coffee reference genome to produce well-supported nuclear trees. We assembled whole chloroplast genome sequences for 27 species of the Rubiaceae subfamily Ixoroideae using next-generation sequences. Analysis of the plastid genome structure reveals a relatively good conservation of gene content and order. Generally, low variation was observed between taxa in the boundary regions with the exception of the inverted repeat at both the large and short single copy junctions for some taxa. An average of 79% of the SNP determined in the Coffea genus are transferable to Ixoroideae, with variation ranging from 35% to 96%. In general, the plastid and the nuclear genome phylogenies are congruent with each other. They are well-resolved with well-supported branches. Generally, the tribes form well-identified clades but the tribe Sherbournieae is shown to be polyphyletic. The results are discussed relative to the methodology used and the chloroplast genome features in Rubiaceae and compared to previous Rubiaceae phylogenies.

Diversity of plant communities in semi-natural grasslands is strongly dependent on management practices. To characterize community diversity and agricultural practices, we need easy-to-use indicators. The diagnostic species are used to characterize and differentiate vegetation types, but are they useful to assess the various facets of community diversity and the agricultural practices applied to managed grasslands? Based on the fidelity analysis of 311 phytosociological releves, considered as references for mesic grassland classification in the Franche-Comte region (eastern France), we identified eight diagnostic species of mesic pastures (Cynosurion cristati). We then compared the number of diagnostic species observed in 45 mountain pastures with taxonomic, phylogenetic and multi-trait functional diversity indices, as well as with agronomic variables describing stocking rate and fertilization. To account for the role of diagnostic species identity, we compared Spearman rank correlations obtained for these diagnostic species with correlations calculated for 1000 random samples of eight species from the regional species pool of mesic grasslands. The number of diagnostic species in the grassland plot was significantly positively correlated with most taxonomic, phylogenetic and functional diversity metrics. However, only the positive correlations with Simpson taxonomic diversity and Rao functional diversity were significantly different from those obtained from random samples. Moreover, the number of diagnostic species was significantly negatively correlated with stocking rate and fertilization intensity, although only correlations with industrial fertilizer input were significantly different from results obtained from random samples. These results show that the number of diagnostic species observed in a pasture may be a good indicator of a high taxonomic and functional diversity and of a low fertilization. Thereby, a special attention should be given to diagnostic species to assess the status of grassland biodiversity, including functional aspects.

Mouly, A. (2016). A new species of Thiollierea Montrouz. (Rubiaceae) on mining land, micro-endemic of the Poum Massif (New Caledonia). Candollea 71: 99–104. In French, English and French abstracts.DOI: http://dx.doi.org/10.15553/c2016v711a12 A new species of Thiollierea Montrouz. (Rubiaceae, Chiococceae) endemic to New Caledonia is described and illustrated. Thiollierea laureana Mouly belongs to the group of species with red and/or yellow flowers. This new taxon is morphologically close to Thiollierea neriifolia (Brongn.) Barrabe & Mouly but differs by its large oblanceolate leaves, solitary flower borne on a short peduncle lacking leafy bracts, and an hypanthium fluted by 10 discrete linear semi-cylindrical ribs. Thiollierea laureana is a New Caledonian micro-endemic, found only on the small ultramafic Poum massif, located at the northern tip of the largest island, Grande Terre. The new species is assessed as “Critically Endangered” using the IUCN Red List Categories and Criteria.

International audience; Understanding how land-use changes affect different facets of plant biodiversity in seminatural European grasslands is of particular importance for biodiversity conservation. As conclusions of previous experimental or synchronic observational studies did not converge toward a general agreement, assessing the recent trends in vegetation change in various grassland systems using a diachronic approach is needed. In this resurvey study, we investigated the recent changes in grassland vegetation of the French Jura Mountains, a region with a long tradition of pastoralism. We compared the floristic composition of 150 grassland plots recorded between 1990 and 2000 with new relevés made in 2012 on the same plots. We considered taxonomic, phylogenetic and functional diversity as well as ecological characteristics of the plant communities derived from ecological indicator values and life strategies of the species. PCA of the floristic composition revealed a significant general trend linked to the sampling year. Wilcoxon paired tests showed that contemporary communities were generally more dominated by grass species and presented a higher tolerance to defoliation, a higher pastoral value, and a higher nutrient indicator value. Comparisons revealed a decrease in phylogenetic and functional diversity. By contrast, local species richness has slightly increased. The intensity of change in species composition, measured by Hellinger distance between pairs of relevés, was dependent on neither the time lag between the two surveys, the author of the first relevé nor its location or elevation. The most important changes were observed in grasslands that previously presented low pastoral value, low grass cover, low tolerance to defoliation, and high proportion of stress-tolerant species. This trend was likely linked to the intensification of grassland management reported in the region, with a parallel increase in mowing frequency, grazing pressure, and fertilization level. More restrictive specifications should be applied to agricultural practices to avoid overexploitation of mountain species-rich grasslands and its negative consequences on their biodiversity and resilience.

Background and aims – Ixora margaretae, endemic to New Caledonia, is a flagship for the archipelago's sclerophyllous forests. Recently, three populations of an Ixora resembling I. margaretae were found in humid forest.Methods – Genetic studies using SSR markers and morpho-anatomical studies of vegetative and reproductive features are provided.Results – Molecular results show that the genetic distances between and within Ixora margaretae dry and humid stands vary similarly. Accordingly, humid stands are interpreted as a part of the broad newly delimited I. margaretae, occurring in fragmented habitats. Morpho-anatomical data show that several features, such as the bark types, the individual height, and the fruit fleshiness result from genetic variability expressed under environmental constraints. However, other features are interpreted as acclimatisation of populations to local conditions, such as the convergent erected receptaculum pollinis for dry and humid stands, obtain by two different anatomical processes. All data suggest that I. margaretae is a species showing genetic isolation and relative adaptations to environments of populations in both humid and sclerophyll forests. This illustrates potential ongoing speciation processes for several populations in both forest types. A scenario showing the successive habitat modifications from humid to sclerophyll forests that can explain the persistence of the species in sclerophyll areas is proposed.

International audience; Taxonomic, functional and phylogenetic diversities can respond differently to biotic and abiotic filters. However, biodiversity management tends to focus on a single index, generally taxonomic diversity, assuming a strong positive correlation among biodiversity components across scales. This can result in a mismanagement of functional and phylogenetic diversities with negative consequences for ecosystem functioning and long-termmaintenance of services. Understanding the relationships among biodiversity components, how they change across scales and which their main drivers are can lead to more sustainable management of biodiversity and its associated ecosystem services and functions. We used an integrative approach of biodiversity where we investigated alpha and beta taxonomic (TD), functional (FD) and phylogenetic (PD) diversity of orthopteran communities as well as species and functional traits composition and their associated drivers at the local and landscape scales in permanent mesic grasslands of the French Jura Mountains. We assessed whether orthopteran TD, FD and PD were positively correlated. We also determined the drivers of TD, FD and PD and their changes across scales and among indices using data related to soil, agricultural practices, elevation, and biotic interactions with plants. Our results showed that (i) elevation was a strong driver of orthopteran community trait composition, (ii) orthopteran alpha TD, FD and PD were correlated among themselves and increased with plant species richness, and (iii) local beta diversity was not correlated with alpha diversity. Beta diversity had different drivers at local and landscape scale: it was influenced by soil chemistry and texture at the local scale and increased with the difference in elevation among plots at the landscape scale. This study evidences distinct processes driving alpha and beta diversity of orthopteran communities at both the local and landscape scales. It supports the hypothesis that less intensive agricultural practices enhance orthopteran diversity and highlights the importance to consider beta diversity at both local and landscape scale when designing and assessing the management regimes of grassland ecosystems. Prioritizing the importance of the different biodiversity components and spatial scales constitutes an important challenge for sustainable grassland management.

International audience; In this study we investigate the large and diverse Rubiaceae-Gardenieae and closely related tribes Bertiereae, Coffeeae, Cremasporeae, Octotropideae, and Pavetteae. Some of the tribes or groups have been shown to be monophyletic and strongly supported, but the phylogeny of this large complex is still far from being satisfactorily elucidated particularly for Gardenieae, both in terms of intertribal relationships as well as tribal delimitations. We reconstruct the phylogeny of the complex using an extensive sampling of 108 genera and five plastid DNA regions. Phylogenetic relationships demonstrate that Gardenieae sensu Andreasen & Bremer is polyphyletic, as Burchellia, Didymosalpinx, Monosalpinx, and Mantalania are closer to Octotropideae-Cremasporeae. In addition, Pavetteae and the investigated members of Aulacocalyceae are nested in a supported but partially unresolved Gardenieae-Pavetteae clade. Within this clade, several strongly supported groups are resolved: an Aidia group, an Alibertia group, a Gardenia group, Pavetteae including Pelagodendron, a Porterandia group, a Randia group, a Rothmannia group (including Aulacocalyx and Heinsenia), a Sherbournia group, and the two isolated genera Massularia and Schumanniophyton. The latter genus presented a high rate of genetic substitutions, which resulted in perturbations of the phylogenetic reconstruction. A revised tribal circumscription is given for Gardenieae, the Alibertia group is recognized at tribal level as an emended Cordiereae, and a new tribe, Sherbournieae, is described to accommodate the members of the Sherbournia group.

International audience; In the past, the circumscription of the large genus Psychotria (Rubiaceae) was difficult, until molecular phylogenetic studies revealed its considerable paraphyly, enabling the delimitation of its major lineages and the grouping of related genera, and most notably the separation of Psychotria and its relatives (former Psychotrieae) into two tribes: Psychotrieae and Palicoureeae. The genus Margaritopsis, which is included in Palicoureeae, encompasses 27 Neotropical species, and in previous studies these have been shown to be close relatives of a group of eight Psychotria species that occur over a large region extending from South-East Asia to tropical South Pacific through Malesia (= the AMP region, defined as including South-East Asia, Malesia, tropical Australia, Melanesia, Micronesia, New Caledonia and Polynesia). A molecular phylogenetic study, using one nuclear DNA region (ITS) and four plastid DNA regions (ndhF, rps16, trnH-psbA, trnT-F), is undertaken in order to test the placement of 17 AMP Psychotria species within Palicoureeae. The phylogenetic results show that they form a monophyletic clade (= clade G), which also includes the monotypic Fijian genus Readea and Hodgkinsonia frutescens from Australia. Clade G is embedded in a well-supported grade with five Neotropical representatives of Margaritopsis. A morphological survey based on twenty characters, with the potential to circumscribe generic entities, shows that the monophyly of clade G is supported by a character combination that is similar to species of Neotropical Margaritopsis, confirming their inclusion in this genus. Taxonomic and nomenclatural work on these species is required to formalize nomenclatural implications. Based on the same set of morphological characters, but in absence of molecular data, 28 other Psychotria species from the AMP region were detected as likely candidates for inclusion in Margaritopsis, allowing the estimation of species richness of clade G to be a minimum of 47 species. Within clade G, five well-supported subclades and a Readea lineage are delimited and each of these is generally supported by unique morphological features. Phylogenetic topologies reveal biogeographical patterns, including a main route of dispersal from western to eastern parts of the AMP region, with subsequent dispersals between archipelagos in the region.

Questions: What is the impact of nitrogen (N) inputs on the vegetation of mountain permanent grasslands? Beyond the effect of fertilizer quantity (total and available N supply), is there a specific effect of fertilizer quality (the various N sources) on the multiple biodiversity facets of plant communities? Location: Jura Mountains (France). Methods: Based on a vegetation and agronomic survey of 29 mown grasslands, we considered taxonomic, phylogenetic and multi-trait functional diversity indices as well as community-weighted means of seven functional traits (CWMs) including CSR strategies. Using partial redundancy analysis (pRDA) and Spearman correlations, we assessed the response of these biodiversity metrics to (1) the medium-term total N input and the short-term available N input of any origin, and (2) the relative contribution of industrial fertilizers, solid manure, liquid manure, livestock restitutions and atmospheric deposition to the amount of available N added to the soil during the year preceding vegetation sampling. Results: We report significant negative rank correlations between total or available N input and two diversity metrics: species richness and functional richness. Among CWMs, high N inputs were positively correlated with specific leaf area (SLA), competitive and ruderal strategies, and negatively with seed mass and stress-tolerant strategy. Results also revealed various trends according to the N source: when the proportion of available N from livestock restitutions was high, plant communities showed higher taxonomic and phylogenetic diversity and lower leaf dry matter content. In contrast, communities receiving mainly industrial fertilizers showed lower taxonomic and phylogenetic diversity and higher SLA. Moreover, pRDA suggested contrasting impacts of the main N source on life strategies: R strategy appeared more favoured by a high proportion of industrial fertilizers, while C strategy was enhanced by liquid or solid manure. Conclusions: Our observations support the common finding that a high N supply impacts plant functional composition and is associated with a decrease in species richness through the loss of stress-tolerant species. In addition, they show that biodiversity patterns mostly depend on fertilizer origin. In particular, industrial fertilizers appear to be the most detrimental sources of nutrients for both taxonomic and phylogenetic diversity in mountain grasslands.

Atractocarpus Schltr. & K.Krause is an Australian and Pacific genus of Gardenieae (Rubiaceae) which includes c. 40 species. The genus was initially described for a species bearing fusiform fruits, and occurring in the southern part of New Caledonia, viz. A. bracteatus Schltr. & K.Krause. Another species, A. heterophyllus (Montrouz.) Guillaumin & Beauvis. with oblong leaves and oblong ovoid fruits was described for New Caledonia, but initially under Gardenia Ellis and this for the North of the archipelago. During later revisions and supplementary descriptions of species in the genus, both species carrying heteromorphic leaves were reconsidered. The name A. bracteatus was placed in synonymy of A. heterophyllus; while keeping a delimitation of the species restricted to the southeastern populations. This situation ended in the re-description of the northern species, named A. balansaeanus Guillaumin. The results of the present work, based on the examination of herbarium specimens and literature, disen...

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.

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.

According to current generic delimitations, supported by wood anatomy, palynology, and recent molecular phylogenies, Antirhea, traditionally treated as a Pantropical genus, is instead restricted to the Paleotropics. At the same time, the Neotropical species traditionally positioned in Antirhea should be positioned in Stenostomum. Following these definitions, Stenostomum is a genus with most of the species present in the Caribbean Region, and two species present in the Guianas, namely S. acreanum and S. guianensis, distributed throughout the Amazon Basin. In addition, according to these new generic delimitations, two species previously positioned in Guettarda and Antirhea need to be transferred to Chomelia, as C. triflora and C. ulei.

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.

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.) Arenes, Pseudopeponidium Homolles ex Arenes, 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 phylo...

We performed phylogenetic analyses of DNA sequences of three chloroplast markers: rbcL, rps16 ,a ndtrnT-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. Halle ´, Doricera Verdc., Hitoa Nadeaud, Myonima Comm. ex Juss., Sideroxyloides Jacq., Thouarsiora Homolle ex Arenes, 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 (2000) is not monophyletic without an exclusion of Scyphiphora. Ixoreae fide Robbrecht and Manen (2006) 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 ,a ndGreenea 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.

Systematique de la tribu des Ixoreae A. Gray (Rubiaceae) : phylogenie, biogeographie et taxonomie : Resume de these d´Etat

During the preparation of the Vascular Flora of the Marquesas Islands and Flore de la Polynesie francaise, four new species of Ixora L. (Rubiaceae) have come to light and are described and illustrated herein: Ixora jourdanii Mouly & J.Florence, Ixora tahuataensis Mouly & J.Florence, Ixora uahukaensis Lorence & W.L.Wagner, and Ixora uapouensis Lorence & W.L.Wagner. In addition to these new taxa, the following three species of Ixora previously described from the Marquesas are recognized: Ixora marquesensis F.Br., Ixora ooumuensis J.Florence, and Ixora spathoidea F.Br. As the Marquesan environment is under serious threat from human impact, feral animals and weeds, the conservation status was estimated for each Ixora species. It is concluded that all Marquesan taxa are in need of inclusion in the IUCN Red List, their status ranging from endangered to critically endangered. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 581–597.

Ixora clarae and I. elisae (Rubiaceae) are two endemic species described from New Caledonia. Ixora clarae is easily recognised by its (1-)3-flowered inflorescences, made up by thick and large flowe ...

The name Cyclophyllum memaoyaense Mouly is here validated by the citation of the holotype location.

New Caledonia, listed as a biodiversity hotspot, is ecologically unique because of the abundance on the main island of ultramafic soils. The Pacific genus Cyclophyllum Hook.f. (Rubiaceae) that belongs to the tribe Vanguerieae has its centre of diversity in New Caledonia, with 13 species described so far. The present taxonomic treatment describes seven species new to science: Cyclophyllum guillauminianum Baum.-Bod. ex Mouly & Jeanson, Cyclophyllum letocartiorum Mouly, Cyclophyllum macphersonii Mouly, Cyclophyllum memaoyaense Mouly, Cyclophyllum pindaiense Mouly, Cyclophyllum tieaense Mouly and Cyclophyllum tiebaghiense Mouly & Jeanson. These new species, all endemic to New Caledonia add to species already described for the genus. A determination key and few synonymies are provided here. These species present a very interesting pattern of narrow endemism probably resulting from adaptation(s) to ultramafic substrates. Indeed, 14 species out of 19 are restricted to constraining soils and 12 species ar...

International audience

Background and aims - Recent methodological and theoretical advances in community ecology have allowed more robust exploration of complementary facets of biodiversity in plant communities. Focusing on semi-natural permanent grasslands of the French Jura Mountains, we assessed how taxonomic, phylogenetic and functional diversity metrics vary among three phytosociological vegetation units. Methods - We selected a sample of 135 releves out of a phytosociological database, depicting three phytosociological orders (Brometalia erecti, Arrhenatheretalia elatioris and Trifolio repentis-Phleetalia pratensis) and including 381 vascular plant species. We built a phylogenetic tree based on sequences of two genes encoding chloroplast proteins, from which we computed phylogenetic diversity metrics that we compared to various taxonomic, single-trait and multi-trait functional metrics, including communityweighted means of functional traits (CWMs). Key results - Most diversity metrics and CWMs significantly differed among vegetation units. Within each facet of biodiversity, the different metrics showed complementary results. Moreover, even when considering diversity metrics comparable in mathematical terms, i.e. based on Rao quadratic entropy, the results were largely non-redundant among the facets of biodiversity. Phylogenetic diversity and multi-trait functional diversity show opposite responses to vegetation units, as well as a low phylogenetic signal. These two results suggest that phylogenetic diversity cannot be used as a simple proxy for functional diversity. Conclusion - This study highlights the importance of taking into consideration different facets for a better understanding of biodiversity. In particular, phylogenetic and functional facets appear highly informative, and could thus be used in addition to taxonomic diversity metrics as indicators of conservation value. © 2014 Botanic Garden Meise and Royal Botanical Society of Belgium.

National audience

International audience; Due to the recent evolution of sequencing techniques, the number of available genomes is rising steadily, leading to the possibility to make large scale genomic comparison between sets of close species. An interesting question to answer is: what is the common functionality genes of a collection of species, or conversely, to determine what is specific to a given species when compared to other ones belonging in the same genus, family, etc. Investigating such problem means to find both core and pan genomes of a collection of species, i.e. genes in common to all the species vs. the set of all genes in all species under consideration. However, obtaining trustworthy core and pan genomes is not an easy task, leading to a large amount of computation, and requiring a rigorous methodology. Surprisingly, as far as we know, this methodology in finding core and pan genomes has not really been deeply investigated. This research work tries to fill this gap by focusing only on chloroplastic genomes, whose reasonable sizes allow a deep study. To achieve this goal, a collection of 99 chloroplasts are considered in this article. Two methodologies have been investigated, respectively based on sequence similarities and genes names taken from annotation tools. The obtained results will finally be evaluated in terms of biological relevance.

National audience

International audience; Background and Aims Previous work on the pantropical genus Ixora has revealed an Afro-Madagascan clade, but as yet no study has focused in detail on the evolutionary history and morphological trends in this group. Here the evolutionary history of Afro-Madagascan Ixora spp. (a clade of approx. 80 taxa) is investigated and the phylogenetic trees compared with several key morphological traits in taxa occurring in Madagascar. Methods Phylogenetic relationships of Afro-Madagascan Ixora are assessed using sequence data from four plastid regions (petD, rps16, rpoB-trnC and trnL-trnF) and nuclear ribosomal external transcribed spacer (ETS) and internal transcribed spacer (ITS) regions. The phylogenetic distribution of key morphological characters is assessed. Bayesian inference (implemented in BEAST) is used to estimate the temporal origin of Ixora based on fossil evidence. Key Results Two separate lineages of Madagascan taxa are recovered, one of which is nested in a group of East African taxa. Divergence in Ixora is estimated to have commenced during the mid Miocene, with extensive cladogenesis occurring in the Afro-Madagascan clade during the Pliocene onwards. Conclusions Both lineages of Madagascan Ixora exhibit morphological innovations that are rare throughout the rest of the genus, including a trend towards pauciflorous inflorescences and a trend towards extreme corolla tube length, suggesting that the same ecological and selective pressures are acting upon taxa from both Madagascan lineages. Novel ecological opportunities resulting from climate-induced habitat fragmentation and corolla tube length diversification are likely to have facilitated species radiation on Madagascar.

International audience; : New Caledonia is a remote archipelago of the South-West Pacific, whose flora is rich, distinctive, and disharmonic. The interest of botanists has long been attracted by the spatio-temporal origin of this flora, but little attention has been paid to the modes of colonization and the diversification processes that have led to the archipelago's modern flora. To date, no explosive plant radiation has yet been highlighted for New Caledonia. A dated phylogenetic framework on the second richest New Caledonian genus - Psychotria s.l. and its allied genera (tribes Psychotrieae and Palicoureeae, Rubiaceae; ca. 85 species) - is provided in this study to explore its patterns of colonization and diversification in the archipelago. This study is based on a comprehensive species sampling, two nuclear and four plastid loci. Results show that New Caledonia was colonized four times by Psychotria and its allied genera during the Neogene long after its mid-Eocene re-emergence from the sea. The Pacific clade of Psychotrieae, one of the largest plant diversifications in the Pacific islands and the Indo-Pacific region, is absent from New Caledonia, possibly due to niche competition. Although the four lineages colonized New Caledonia relatively simultaneously during the Neogene, they express different evolutionary histories, as revealed by unevenness in species richness and net diversification rates. The genus Geophila has not diversified on New Caledonia, as a non-endemic single species has been documented in the archipelago. The genus Margaritopsis had a moderate level of diversification (four species) similar to that on other Pacific islands. The Psychotria clade NC1 appears to be a relictual lineage, which probably underwent a drastic extinction, with a narrow ecological habitat and dispersal limitations. The Psychotria clade NC2 is the largest and youngest New Caledonian plant radiation, and has undergone the fastest recorded diversification of any endemic lineage in the archipelago, and could be the result of a 'non-adaptive radiation', originating from Australian rainforests.

International audience

Le dernier traitement taxonomique des espèces néo-calédoniennes du genre Psychotria s.l. (Rubiaceae) remonte à plus de 50 ans. L'abondance des noms publiés rend ardue toute étude systématique portant sur le groupe. Une révision nomenclaturale est proposée afin de faire le tri entre les noms valides, invalides, et illégitimes au sein des deux genres Psychotria s.s. et Margaritopsis C.Wright (anciennement placé sous Psychotria s.l.). Des lectotypifications sont effectuées pour des noms d'espèces déjà décrites et pour les deux genres Delpechia Montrouz. et Dourrea Montrouz. Des noms nouveaux et des combinaisons nouvelles sont établis afin d'accorder les noms d'espèces aux règles du Code International de Nomenclature pour les algues, champignons et plantes. Suite à la mise en synonymie de plusieurs noms de taxons spécifiques et variétaux, les noms corrects pour les 59 espèces acceptées pour Psychotria s.s. et trois pour Margaritopsis sont finalement retenus. Il reste néanmoins quatre noms dont le statut est incertain. La richesse spécifique néo-calédonienne devrait être élargie à 85 espèces, réparties entre Psychotria s.s. et Margaritopsis, compte tenu de la découverte d'espèces nouvelles non décrites, autant dans les herbiers consultés que sur le terrain.

International audience; Deux espèces nouvelles de Thiollierea (Rubiaceae) endémiques de Nouvelle-Calédonie sont décrites et illustrées. Une clé de détermination des espèces du genre Thiollierea est donnée. Thiollierea rigaultii sp. nov. et T. dagostinii sp. nov. appartiennent au groupe des espèces à fleurs blanches et violacées. Thiollierea rigaultii sp. nov. possède des caractères uniques pour ce groupe : inflorescences unifl ores, face interne du calice totalement recouverte par des cérocystes, corolle coriace et de grande taille. Thiollierea 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 ultramafique 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 flore 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).