Three new species of Tricalysia (Rubiaceae) from Atlantic Central Africa

Background and aims – The genus Tricalysia A.Rich. (Rubiaceae), regarded here in the strict sense (i.e., excluding Empogona Hook.f.), includes 77 species in tropical Africa, Madagascar and the Comoros. In the current paper, three new species from Atlantic Central Africa are described and illustrated; their conservation status is also assessed.Material and methods – This paper is based on a study of herbarium collections from BR, BRLU, K, LBV, P, WAG and YA. Normal practices of herbarium taxonomy have been applied. The conservation status assessments follow the IUCN Red List criteria.Results – Tricalysia lophocarpa O.Lachenaud & Sonké is endemic to Gabon and is best recognised by its fruits with 8–10 narrow longitudinal ribs. Tricalysia obovata O.Lachenaud & Sonké is endemic to Equatorial Guinea (Rio Muni) and may be recognised by its obovate leaves with rounded base, glabrous stems, and sessile flowers with included style and half-exserted anthers. Tricalysia wilksii O.Lachenaud & Sonké occurs in Gabon and southwestern Republic of Congo, and may be recognised by its glabrous stems and leaves, the latter with crypt domatia, its linear calyx teeth equalling or exceeding the tube in length, and its shortly pedicellate fruits. The three species are assessed respectively as Near-threatened (T. lophocarpa), Critically Endangered (T. obovata) and Vulnerable (T. wilksii)

Novitates Gabonenses 93: a fresh look at Podostemaceae in Gabon following recent inventories, with a new combination for Ledermanniella nicolasii

Background and aims – Podostemaceae is a family of strictly aquatic plants found in rapids and waterfalls. Despite a recent treatment in the Flore du Gabon, the family remained poorly known, with no major studies including Gabonese collections, and almost no targeted inventories since 1966. We present the first large-scale inventory of this family in Gabon, targeting Podostemaceae throughout the country, providing new additions to the flora of Gabon and many new records of poorly known species. Material and methods – Fieldwork was conducted in Gabon between 2017 and 2021. The collected specimens were primarily preserved in ethanol with associated silica gel-preserved material and photographs. Material available at BR, BRLU, LBV, MO, P, WAG, and Z/ZT was examined. For each species, information on distribution and ecology is presented, as well as a distribution map in Gabon. Key results – The 500 newly collected specimens represent 91.4% of all known collections of Podostemaceae from Gabon. Three taxa are newly recorded for the country, including one genus (Inversodicraea tenax, Ledermanniella schlechteri, and Saxicolella nana). New distribution records are also presented for 13 little-known species. Four taxa are excluded from the Gabonese flora (the genus Dicraeanthus, Inversodicraea ledermannii, Ledermanniella sanagaensis, and Macropodiella garrettii). To date, 20 species belonging to five different genera are known to occur in Gabon. A new combination is proposed for Ledermanniella nicolasii, and Inversodicraea tanzaniensis is now considered as a synonym of Inversodicraea tenax

14,000 years of climatic and anthropogenic change in the Afromontane forest of São Tomé Island, Gulf of Guinea

São Tomé (Gulf of Guinea, Central Africa) is a 854 km2 tropical island that had a pivotal role in early European colonial expansion through the Atlantic between the 15th and 16th centuries. Historical sources suggest that native vegetation has been heavily impacted since human arrival (1470 CE) due to monoculture economies and the introduction of mammals and plants, some of which now have established wild populations. The Afromontane forest of São Tomé, located above 800 m.a.sl., is particularly rich in endemic plant species and has remained relatively unaffected by direct human impacts. Here, we explore how environmental change influenced this forest through the study of a sedimentary sequence from the volcanic crater of Lagoa Amélia (1340 m a.s.l.), a palustrine system located at the boundary between submontane (800–1400 m a.s.l.) and mist forest (above 1400 m a.s.l.). We used fossil pollen, non-pollen palynomorphs, sedimentology and charcoal to determine forest dynamics from the Late Pleistocene to the present. From 14,000 to 12,500 cal yr BP the forest was dominated by taxa from higher altitudes, adapted to cooler and drier climates (e.g. Afrocarpus mannii trees and Psychotria nubicola). After 12,500 cal yr BP, a potential uphill migration was identified by an increase in taxa like the trees Symphonia globulifera and Craterispermum cerinanthum. From 11,200 cal yr BP through the rest of the Holocene taxa from lower altitudes became dominant (e.g. Prunus africana, Polyscias, and Sabicea), except at c. 8500 cal yr BP when rapid cooling led to forest opening. Charcoal showed that fires were frequent during the Late Pleistocene (14,000 to 11,200 cal yr BP), becoming rare during the Holocene until anthropogenic fires started at c. 220 cal yr BP. Other recent anthropogenic impacts detected in Lagoa Amélia included the appearance of pollen of introduced plant species (e.g., Cestrum), and the increase in pollen of economically important species (Elaeis guineensis, Zea mays) and in fungal spores related to introduced herbivores. Our results reveal that climate changed the altitudinal distribution of the Afromontane forest in São Tomé during the Late Pleistocene, as observed on the African continent, and that this ecosystem was also strongly impacted by human arrival, through fire, farming, and introduced species.info:eu-repo/semantics/publishedVersio

The global abundance of tree palms

Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests

Le genre <i>Stolzia</i> (Orchidaceae) en Afrique centrale avec deux nouveaux taxons

Les taxons du genre Stolzia Schltr. (Orchidaceae) présents en Afrique centrale sont révisés. Neuf taxons ont été identifiés. Deux nouveaux taxons collectés au Cameroun et en Guinée Équatoriale (Rio Muni et Bioko) sont décrits et illustrés. Stolzia repens (Rolfe) Summerh var. cleistogama Stévart, Droissart & Simo diffère des deux autres variétés déjà décrites par son sépale dorsal soudé aux sépales latéraux sur plus d’un tiers de sa longueur, ainsi que par ses pièces florales plus petites et non réfléchies. Stolzia grandiflora P.J.Cribb subsp. lejolyana Stévart, Droissart & Simo est proche de la sous-espèce type, endémique d’Éthiopie, mais présente une inflorescence biflore plus longue et des fleurs plus petites. Il se rapproche également des différentes variétés de Stolzia repens (Rolfe) Summerh., mais s’en distingue par son inflorescence biflore et un pédoncule plus long et plus fin. Stolzia cupuligera (Kraenzl.) Summerh. et S. peperomioides (Kraenzl.) Summerh. sont néotypifiés. Une nouvelle combinaison est proposée, Stolzia peperomioides (Kraenzl.) Summerh. subsp. thomensis (Stévart & P.J.Cribb) Stévart, Droissart & Simo. Plusieurs nouvelles signalisations sont données. Une clé d’identification et un tableau synoptique des taxons présents en Afrique centrale sont proposés.A taxonomic revision of genus Stolzia (Orchidaceae) occurring in central Africa is given. Nine taxa are recognized. Two new taxa from Cameroon and Equatorial Guinea (Rio Muni) are described and illustrated. Stolzia repens (Rolfe) Summerh. var. cleistogama Stévart, Droissart & Simo differs from the two other varieties of S. repens by its dorsal sepal, which is jointed to lateral sepal on one third of his total length, and by its smaller and non-reflected sepals and petals. Stolzia grandiflora P.J.Cribb subsp. lejolyana Stévart, Droissart & Simo is morphologically close to the type subspecies, endemic to Ethiopia, but differs from it by a longer inflorescence with two flowers that are smaller. The morphological affinity of S. grandiflora subsp. lejolyana appears to lie with the varieties of S. repens (Rolfe) Summerh. However, the new species differs by having inflorescences with two flowers and a longer and thinner peduncle. Stolzia cupuligera (Kraenzl.) Summerh. and S. peperomioides (Kraenzl.) Summerh. are neotypified. The position of S. thomensis Stévart & P.J.Cribb is reconsidered and proposed as S. peperomioides (Kraenzl.) Summerh. subsp. thomensis (Stévart & P.J.Cribb) Stévart, Droissart & Simo. Many new records of Stolzia are given. Key to identification of species and synopsis table of all taxa occurring in central Africa are given

Contribution à l’étude des Orchidaceae de Madagascar. XXXVIII. Deux nouvelles espèces et une nouvelle combinaison pour le genre <i>Pectinariella</i> Szlach., Mytnik & Grochocka à Madagascar

Avant son décès, Jean Bosser (23 décembre 1922-6 décembre 2013) travaillait à la publication de deux espèces d’Angraecopsis Kraenzl. Le manuscrit n’ayant pas été publié, nous avons entrepris de poursuivre ce travail en nous basant également sur du matériel supplémentaire que nous avons récolté dans l’est de Madagascar. L’étude de ces échantillons nous a permis de déterminer que ces espèces appartiennent au genre Pectinariella Szlach., Mytnik &amp; Grochocka et que l’une des deux espèces n’est en fait pas nouvelle, mais correspond à Pectinariella pterophylla (H. Perrier) Verlynde &amp; Ramandimbisoa, comb. nov., dont nous reprécisons les limites morphologiques. Nous publions la deuxième espèce sous le nom de Pectinariella edmundi Bosser ex Verlynde &amp; Ramandimbisoa, sp. nov. Enfin, une troisième espèce, endémique des forêts de l’est de Madagascar, qui possède un ensemble de caractères floraux inédits pour ce genre, est décrite ici, Pectinariella scroticalcar Verlynde &amp; Ramandimbisoa, sp. nov. Pour chaque espèce, nous fournissons le statut de conservation, une illustration, ainsi que des notes sur l’écologie et la distribution. Une clef des six espèces de Pectinariella présentes à Madagascar est aussi proposée.Before passing away, Jean Bosser (23rd of December 1922-6th of December 2013) worked on describing two species of Angraecopsis Kraenzl. The manuscript has never been submitted for publication, we thus undertook to complete his work using specimens we collected in Eastern Madagascar. The study of these specimens allowed us to determine that the two species belong to the genus Pectinariella Szlach., Mytnik &amp; Grochocka and that one of these two species was not a novelty but corresponded rather to Pectinariella pterophylla (H. Perrier) Verlynde &amp; Ramandimbisoa, comb. nov., for which we redefine morphological delimitation. We publish the second species under Pectinariella edmundi Bosser ex Verlynde &amp; Ramandimbisoa, sp. nov. Finally, Pectinariella scroticalcar Verlynde &amp; Ramandimbisoa, sp. nov., a third species, endemic to the eastern forests of Madagascar and possessing novel floral characteristics for the genus, is described. For each species, we provide conservation status, illustrations as well as ecological and distribution notes. A determination key of the six species of Pectinariella found in Madagascar is given.</p

A new species of &lt;i&gt;Bertiera&lt;/i&gt; Aubl. (Rubiaceae) in subgenus &lt;i&gt;Bertierella&lt;/i&gt; discovered in Equatorial Guinea and Cameroon

Une nouvelle espèce de Bertiera (Rubiaceae) de Guinée Équatoriale et du Cameroun, Bertiera rosseeliana Sonké, Esono &amp; Nguembou, est décrite et illustrée ici. Cette nouvelle espèce appartient au sous-genre Bertierella et semble très proche de Bertiera naucleoides. Le nouveau taxon diffère néanmoins de cette espèce par de nombreux caractères énumérés dans la diagnose : ses feuilles à limbe glabre sur les deux faces ; le tube de la corolle plus long (18-20 et non 5-6 mm), les lobes du calice plus courts (2-3 et non 7-8 mm) ; les fruits sans pédicelle.A new species of Bertiera (Rubiaceae) from Equatorial Guinea and Cameroon, Bertiera rosseeliana Sonké, Esono &amp; Nguembou, is described and illustrated here. This new species belongs to subgenus Bertierella and appears to be closely related to Bertiera naucleoides. It differs from this species, however, by the features stated in the diagnosis: glabrous leaf blade (not puberulous); calyx lobes shorter (2-3 not 7-8 mm); corolla tube longer (18-20 not 5-6 mm); fruits without pedicel.</p

Notes taxonomiques et chorologiques sur quelques Orchidaceae endémiques d&#039;Afrique centrale atlantique

En 1997, le manque de données disponibles sur les Orchidaceae Juss. d’Afrique centrale atlantique et l’importance des menaces pesant sur la forêt africaine, comme sur les épiphytes qu’elles abritent, nous ont amenés à entreprendre une vaste campagne d’échantillonnage sur l’ensemble de cette région. L’examen du matériel récolté et des collections historiques a permis des avancées taxonomiques sur un grand nombre d’espèces endémiques de la région, ou jusqu’à présent considérées comme telles, et a abouti à la mise à jour de leurs aires de distribution. Des mises en synonymie sont proposées : Ancistrorhynchus constrictus Szlach. &amp; Olszewski est inclus dans Ancistrorhynchus capitatus (Lindl.) Summerh. ; Bulbophyllum mayombeense Garay est mis en synonymie de Bulbophyllum schinzianum Kraenzl. var. schinzianum ; et Bulbophyllum kupense P.J.Cribb &amp; B.J.Pollard devient synonyme de Bulbophyllum teretifolium Schltr. Une néotypification est faite pour cette dernière espèce, de même que pour Liparis goodyeroides Schltr. La distribution géographique de plusieurs taxons est modifiée : Aerangis megaphylla Summerh. est bien endémique de l’île d’Annobon, Polystachya superposita Rchb.f. est de nouveau considéré comme endémique du Cameroun et Liparis suborbicularis Summerh. n’est plus signalé qu’au Nigeria et au Cameroun. Trois nouvelles signalisations sont mentionnées : Aerangis bouarensis Chiron pour le Cameroun, Bulbophyllum schinzianum Kraenzl. var. schinzianum pour la République du Congo et Liparis goodyeroides Schltr. pour le Liberia. Les statuts de conservation selon les catégories et critères de l’IUCN sont donnés pour chaque taxon.The paucity of distributional data on Orchidaceae Juss. of Central Atlantic Africa along with the severity of threats to humid forests in Africa and to their epiphytes, led us in 1997 to undertake an intensive sampling campaign in this region. Analysis of the new specimens generated and examination of historical collections have resulted in a number of taxonomic advances regarding several endemic species of Atlantic Central Africa, or previously considered as endemic, and have resulted in updates of their known ranges. The following taxonomic changes are made: Ancistrorhynchus constrictus Szlach. &amp; Olszewski is placed in synonymy under Ancistrorhynchus capitatus (Lindl.) Summerh.; Bulbophyllum mayombeense Garay is placed in synonymy under Bulbophyllum schinzianum Kraenzl. var. schinzianum; and B. kupense P.J.Cribb &amp; B.J.Pollard is placed in synonymy under B. teretifolium Schltr., for which a neotype is designated. The geographical distribution of several taxa is amended: Aerangis megaphylla Summerh. is shown to be endemic to the island of Annobon; Polystachya superposita Rchb.f. is recognized as endemic to Cameroon, and Liparis suborbicularis Summerh. is known only from Nigeria and Cameroon. Three new records are indicated: Aerangis bouarensis Chiron for Cameroon, Bulbophyllum schinzianum Kraenzl. var. schinzianum for the Republic of Congo, and Liparis goodyeroides Schltr. for Liberia. Conservation assessments based on IUCN categories and criteria are provided for each taxon

A revised concept of Rhipidoglossum (Angraecinae, Orchidaceae)

International audienceFollowing the production of a near-comprehensive generic phylogenetic analysis of African angraecoid orchids, paraphyly of the genus Rhipidoglossum relative to Cribbia, Margelliantha and Rhaesteria was in need of being resolved by integrating morphological observations into this newly available molecular framework. Accordingly, we critically revised the diagnostic traits of each genus by examining about 700 herbarium specimens ascribable to 50 species of Rhipidoglossum and its satellite genera. Cribbia, Margelliantha and Rhaesteria are here lumped with Rhipidoglossum, along with Angraecopsis pusilla and Diaphananthe millarii. The presence of pollinaria with two separate disk-shaped viscidia, a trilobed, non-papillate rostellum with midlobe more prominent than lateral lobes and an undivided lip are diagnostic of this more inclusive concept of Rhipidoglossum. In line with this new taxonomic arrangement, 11 new combinations in Rhipidoglossum are made, and Margelliantha lebelii is moved to Diaphananthe and first reported for Uganda