Deux nouveaux taxons appartenant à la section Lomatophyllum Rowley du genre Aloe L. (Xanthorrhoeaceae, Asphodelaceae), et en provenance de Madagascar, A. maningoryensis J.-P. Castillon, sp. nov., et A. alaotrensis J.-P. Castillon, sp. nov., sont décrits ici. Le premier de ces taxons est morphologiquement intermédiaire entre A. occidentalis (H. Perrier) Newton & Rowley de la côte ouest malgache et A. orientalis (H. Perrier) Newton & Rowley de la côte est ; il pousse sur les hauts-plateaux, dans les forêts bordant le lac Alaotra. Le deuxième taxon, originaire de la même région, est quant à lui morphologiquement intermédiaire entre A. propagulifera (Rauh) Newton & Rowley et A. socialis (Perrier) Newton & Rowley. Ces deux espèces sont particulièrement intéressantes car elles relient plusieurs groupes de Lomatophyllum qu'on pouvait croire éloignés et confirment ainsi l'unité de la section.

Le présent article constitue une mise au point nomenclaturale du genre Khaya A. Juss., circonscrit à l'Afrique continentale, Madagascar et aux Comores. Ce genre contient un petit nombre de taxons, de quatre à six espèces selon les auteurs. Les noms publiés par le passé ne sont pas toujours rattachés à un type approprié ou nécessitent d'effectuer un choix parmi les syntypes. À la lumière de la bibliographie et de l'examen exhaustif des échantillons d'herbier, nous avons procédé à dix lectotypifications pour des taxons pour lesquels cela s'avérait nécessaire, ainsi qu'à une épitypification, afin de se conformer aux règles du Code international de Nomenclature botanique.

The bark structure of Adansonia digitata L. is described in detail. Characters of the bark that are shared with other Malvaceae include the presence of strongly dilating rays, mucilage cells and cavities, druses of calcium oxalate in the cells of cortical parenchyma and phloem rays, a storied arrangement of sieve tube members and axial parenchyma strands, the presence of secondary phloem fibers and their arrangement into tangential bands. The secondary phloem fibers are longer (2.8–8.6 mm) and more abundant than the libriform fibers (1.7–2.2 mm) in the wood of this species. The abundance of parenchyma in both axial and radial parts of the secondary phloem and in the pseudocortex is a noteworthy feature. Due to the complementarity of fibrous and parenchymatous tissues, the secondary phloem can provide substantial mechanical benefits and apparently play an important role in the biomechanical stability of the trunk. The meristematic capacity of dilated phloem rays and the pseudocortex allow for substantial bark dilatation with very limited abscission of the outer portions of the secondary phloem. Subsequent phellogen initiation in the outer part of the secondary phloem was not observed, not even in mature bark. Hence no rhytidome is present. The thin translucent phellem, formed by continuous phellogen arising in the subepidermal layer, allows for photosynthesis to potentially occur within the chloroplast-containing cells of phelloderm and pseudocortex, even when the plants are leafless, thus probably assisting them to survive harsh climatic conditions. The formation of sieve tube members by transverse anticlinal divisions from fusiform cambial initials in A. digitata is a first report for the Malvaceae sensu lato.

The genus Psychotria L. (Rubiaceae) is one of the most diverse in the Pacific, including the islands of French Polynesia with 28 described endemic species. The Psychotria speciosa G. Forst. complex is evaluated, and P. speciosa is lectotypified and an epitype designated. The new combination Psychotria trichocalyx (Drake) Fosberg ex J.-Y. Meyer, Lorence & J. Florence, comb. nov., is made based on Calycosia (Uragoga) trichocalyx. The new species Psychotria paulae J.-Y. Meyer, Lorence & J. Florence, sp. nov., endemic to Tahiti (Society Islands), is described and illustrated. It differs from the closely related Psychotria speciosa by having leaves with longer petioles (up to 5 cm long), flowers fewer per inflorescence (1–3) and with longer pedicels up to 15 mm long, calyx with longer tube and short lobes, a 5–7-lobed corolla, longer fruit pedicels up to 4 cm long, and cylindrical to ovoid fruits 2–3 cm long. The conservation of this extremely rare species, known from only one locality on Tahiti and directly threatened by invasive alien plants (proposed IUCN status: CR), is a priority.

Marsdenia R.Br. represents the largest group of Asclepiadoideae in New Caledonia. With five new endemic species described here, and one new combination, the number of Marsdenia species increases to 18 for New Caledonia. The new species are all restricted to ultramafic substrates. Marsdenia kaalensis Meve, Gâteblé & Liede, sp. nov. is only known from the Mt. Kaala area in northwestern Grande-Terre, and M. weberlingiana Liede, sp. nov. is restricted to one locality at Hô (Houaïlou). In contrast, the other three species (Marsdenia mackeeorum Meve, Gâteblé & Liede, sp. nov., M. neocaledonica Meve, Gâteblé & Liede, sp. nov. and M. paulforsteri Meve, Gâteblé & Liede, sp. nov.) are fairly widely distributed and locally common. All new species are fully illustrated, and a distribution map is provided. Moreover, the new combination Marsdenia guillauminiana (P.T.Li) Meve, Gâteblé & Liede, comb. nov. (based on Tylophora guillauminiana P.T.Li) is proposed for this rare endemic, originally described as Tylophora micrantha Guillaumin. Tylophora anisotomoides Schltr., syn. nov., instead, is proposed as a new and additional synonym of Vincetoxicum biglandulosum (Endl.) Kunze.

Our objective was to study reproductive biology, seed germination and regeneration, through morphoanatomical and field observations and controlled experiments, to assess reproductive strategies in six rare Flourensia endemic to Central Argentina (F. campestris, F. hirta, F. leptopoda, F. niederleinii, F. oolepis, F. tortuosa). Structure of capitula, flowers, and achenes was described. Capitula were visited by a variety of insects. Achenes required 30–45 days to mature. Fruit set varied significantly among species. Flourensia campestris and F. oolepis were self-incompatible. Seed viability decreased after 19 months and was lost after 32 months. Flourensia oolepis and F. campestris had the highest germination percentages (>60%); the addition of gibberellic acid in 2-months old seeds did not influence germination. The remaining species had lower germination percentages (<30%). All species had xylopodia that were root and stem modifications. Burned individuals of F. campestris actively regenerated from underground buds of xylopodia, being suitable for restoration of degraded or burned areas. Flourensia campestris and F. oolepis had better reproductive success, but the remainder species can be considered at risk. Strategies should be implemented to protect them, such as to preserve its habitat together with attempts to increase their population sizes and maintain their pollinators.