Endemic families of Madagascar. XII. Resurrection and taxonomic revision of the genera Mediusella (Cavaco) Hutchinson and Xerochlamys Baker (Sarcolaenaceae)

[摘要] ThepositionofLeptolaenasubgeneraMediusellaCavacoandXerochlamys(Baker)CavacowithrespecttoLeptolaenaThouarsandSarcolaenaThouarshaslongbeendebatedalongwiththecircumscriptionofspecieswithinthesetwogroups.RecentadvancesinthemolecularphylogenyofSarcolaenaceaeindicatethatbothMediusellaandXerochlamysarenotpartofLeptolaena,requiringagenericrecircumscriptionoftheentitiesintheLeptolaena-Sarcolaena-Mediusella-Xerochlamysclade.TheresultsofapreviousmultivariateanalysisofmorphologicalcharactersalsoshowedthatMediusellaandXerochlamysincludetwoandeightentitiesrespectively,whicharerecognizedhereasdistinctspecies.ThreespeciesofXerochlamys(X.coriacea,X.itremoensisandX.undulata)aredescribedasnew,andMediusellaarenariarequiresanewcombination.Thethreenewspeciesaredistinguishedbytheirhabit,thesize,pubescenceandmarginoftheirleaves,andthestructureoftheirinflorescences.Akeytothespeciesandinformationontheirdistribution,ecologyandphenologyaregiven.TheconservationstatusofeachspeciesisevaluatedaccordingtoIUCNRedListcriteria;sixspeciesareconsideredendangered(EN),twoarevulnerable(VU),oneisnearthreatened(NT)andthelastisofleastconcern(LC).

[学科分类] 植物学

[关键词] Sarcolaenaceae;Mediusella;Xerochlamys;endemic;Madagascar;conservation;new species;Sarcolaenaceae;Mediusella;Xerochlamys;endémique;Madagascar;conservation;espèces nouvelles