ABSTRACT
Caesalpinioideae is the second largest subfamily of legumes (Leguminosae) with ca. 4680 species and 163 genera. It is an ecologically and economically important group formed of mostly woody perennials that range from large canopy emergent trees to functionally herbaceous geoxyles, lianas and shrubs, and which has a global distribution, occurring on every continent except Antarctica. Following the recent re-circumscription of 15 Caesalpinioideae genera as presented in Advances in Legume Systematics 14, Part 1, and using as a basis a phylogenomic analysis of 997 nuclear gene sequences for 420 species and all but five of the genera currently recognised in the subfamily, we present a new higher-level classification for the subfamily. The new classification of Caesalpinioideae comprises eleven tribes, all of which are either new, reinstated or re-circumscribed at this rank: Caesalpinieae Rchb. (27 genera / ca. 223 species), Campsiandreae LPWG (2 / 5-22), Cassieae Bronn (7 / 695), Ceratonieae Rchb. (4 / 6), Dimorphandreae Benth. (4 / 35), Erythrophleeae LPWG (2 /13), Gleditsieae Nakai (3 / 20), Mimoseae Bronn (100 / ca. 3510), Pterogyneae LPWG (1 / 1), Schizolobieae Nakai (8 / 42-43), Sclerolobieae Benth. & Hook. f. (5 / ca. 113). Although many of these lineages have been recognised and named in the past, either as tribes or informal generic groups, their circumscriptions have varied widely and changed over the past decades, such that all the tribes described here differ in generic membership from those previously recognised. Importantly, the approximately 3500 species and 100 genera of the former subfamily Mimosoideae are now placed in the reinstated, but newly circumscribed, tribe Mimoseae. Because of the large size and ecological importance of the tribe, we also provide a clade-based classification system for Mimoseae that includes 17 named lower-level clades. Fourteen of the 100 Mimoseae genera remain unplaced in these lower-level clades: eight are resolved in two grades and six are phylogenetically isolated monogeneric lineages. In addition to the new classification, we provide a key to genera, morphological descriptions and notes for all 163 genera, all tribes, and all named clades. The diversity of growth forms, foliage, flowers and fruits are illustrated for all genera, and for each genus we also provide a distribution map, based on quality-controlled herbarium specimen localities. A glossary for specialised terms used in legume morphology is provided. This new phylogenetically based classification of Caesalpinioideae provides a solid system for communication and a framework for downstream analyses of biogeography, trait evolution and diversification, as well as for taxonomic revision of still understudied genera.
ABSTRACT
The present work represents the first comprehensive taxonomic revision of Acacia sens. lat. (Leguminosae: Mimosoideae) in China, focusing on the indigenous species. Critical reassessments of specimens and re-definition of previously recorded species have resulted in recognising 21 indigenous species under Senegalia, a segregate of the former Acacia sens. lat. Detailed botanical profiles are provided for these species, together with a diagnostic line drawing and distribution map; photographs of living plants are provided for more than half the species. Terser treatments are also provided for the 15 species from four genera that are regarded as major introductions of Acacia sens. lat. to the country: Acacia Mill. (12 spp.), Acaciella Britton & Rose (1 sp.), Senegalia Raf. (1 sp.) and Vachellia Wight & Arn. (1 sp.). An identification key to all Acacia sens. lat. species in China is provided. The indigenous species of Senegalia in China belong to sect. Monacanthea (Vassal) Maslin, comb. nov., and the introduced ones to sect. Senegalia. As a consequence of this study, the number of Senegalia species now recognised for China has almost doubled. Six new species are described: Senegalia clandestina Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia guangdongensis Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia obliqua Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia orientalis Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia prominens Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov.; Senegalia stipitata Maslin, B.C.Ho, H.Sun & L.Bai, sp. nov. Four new combinations are established: Senegalia garrettii (I.C.Nielsen) Maslin, B.C.Ho, H.Sun & L.Bai, comb. & stat. nov.; Senegalia kerrii (I.C.Nielsen) Maslin, B.C.Ho, H.Sun & L.Bai, comb. & stat. nov.; Senegalia kunmingensis (C.Chen & H.Sun) Maslin, B.C.Ho, H.Sun & L.Bai, comb. & stat. nov.; Senegalia macrocephala (Lace) Maslin, B.C.Ho, H.Sun & L.Bai, comb. nov. Senegalia andamanica (I.C.Nielsen) Maslin, Seigler & Ebinger and S. macrocephala are new records for China. A lectotype is designated for Acacia teniana Harms and 2nd step lectotypifications effected for Acacia delavayi Franch., Acacia insuavis Lace, Acacia pruinescens Kurz and Acacia yunnanensis Franch. Former holotype citations are corrected to lectotype for Acacia hainanensis Hayata, Acacia macrocephala Lace, Acacia oxyphylla Graham ex Benth. and Acacia philippinarum Benth. A neotype is designated for Acacia arrophula D.Don. China is a principal area of species-richness for Senegalia in Asia. Senegalia displays a high degree of endemism within China and almost half the species are endemic or near-endemic, with Yunnan the most species-rich and species-diverse Province.
