Two new species of Aloe (Asphodelaceae) from the Eastern Humid Forest of Madagascar

Two new species of Aloe were found in the eastern rainforest of Madagascar during a Kew Madagascar Conservation Centre (KMCC) Team expedition in November 2014. The first species, Aloe vatovavensis is rare in this habitat. The second, Aloe rakotonasoloi, exhibits characters that are intermediate between the features of Aloe s.str. and the related genus Lomatophyllum (now Aloe sect. Lomatophyllum). Despite being one of the most species-rich areas for plant diversity, only a few species of Aloe—typically those of Aloe sect. Lomatophyllum—have been recorded in the eastern rainforest of Madagascar to-date

Phylogeny and taxonomy of Afrocayratia, a new genus of Vitaceae from continental Africa and Madagascar

The genus Cayratia Juss. in the traditional sense (i.e., Cayratia s.l.) of the grape family has been shown to be non-monophyletic. Previous studies supported the splitting of Cayratia s.l. into three genera, that is, Cayratia s.s., Causonis Raf., and a new genus representing the African Cayratia clade. However, the morphology of the African Cayratia clade has not been studied carefully and its phylogenetic position within Vitaceae remains unclear. Our study integrates molecular, distributional, and morphological data and supports the recognition of the new genus Afrocayratia from continental Africa and Madagascar. Phylogenetic analyses strongly support the monophyly of Afrocayratia and resolve it as a sister of Cayratia s.s. based on the chloroplast data, but it is placed sister to Cyphostemma based on the internal transcribed spacer dataset. Molecular dating suggests that Afrocayratia split with Cayratia s.s. during the Paleocene, but that the extant species of Afrocayratia did not diversify until the early Miocene. Afrocayratia differs from its allied genera in having short stigmas and seeds with subcircular ventral infold cavities in cross-section. Three clades are detected within Afrocayratia, with A. debilis (Baker) J.Wen & L.M.Lu as the first diverged lineage. The second diverged lineage includes A. delicatula (Willems) J.Wen & Z.D.Chen and A. gracilis (Guill. & Perr.) J.Wen & Z.D.Chen. The third diverged lineage includes A. imerinensis (Baker) J.Wen & L.M.Lu, A. longiflora (Desc.) J.Wen & Rabarijaona, and A. triternata (Baker) J.Wen & Rabarijaona from Madagascar, which form a monophyletic group that diverged from the second lineage in the middle Miocene. Combining the morphological and molecular evidence, we formally describe the new genus Afrocayratia, make seven new combinations, and provide a key to species of the genus

Cyphostemma calcarium (Vitaceae), a new species from Ankarana Special Reserve, Madagascar

Cyphostemma calcarium is herein described as a new species on the limestone outcrops in northern Madagascar. Its diagnostic morphological characteristics were compared to the species occurring in Ankarana Special Reserve. We present detailed descriptions, illustrations, distribution map, and a preliminary conservation assessment of the species. An identification key to all known species from Ankarana Special Reserve is also provided

Cyphostemma calcarium, a new species of Vitaceae from the Ankarana Special Reserve, Madagascar

Cyphostemma calcarium Rabarij & L.M.Lu, sp. nov., is herein described as a new species found on limestone outcrops in northern Madagascar. Its diagnostic morphological characteristics were compared to the species occurring in the Ankarana Special Reserve. We present detailed descriptions, illustrations, distribution map, and a preliminary conservation assessment of the species. An identification key to all known species of Cyphostemma from the Ankarana Special Reserve is also provided

The ghost fruits of Madagascar: Identifying dysfunctional seed dispersal in Madagascar's endemic flora

Madagascar lost a large number of large-bodied animal species during the Holocene. Many of them played important roles as seed dispersers. In the case of the largest-seeded species, giant lemurs or elephant birds may have been the sole dispersers because no extant frugivore has a gape size large enough to ingest those seeds. These plant species now show all the hallmarks of anachronistic species. The consequences of dispersal gaps caused by megafaunal extinctions are exacerbated by the continuing decline of the range distribution of extant dispersers, particularly lemurs. In this paper, we identify dispersal gaps in Madagascar and highlight dysfunctional seed dispersal – systems in which plants have lost animal mutualists. We obtained data on seed dispersal, traits and distribution of plants and frugivores in Madagascar from the literature, online databases, and using herbarium specimens. We estimated the number of potential dispersers for each endemic endozoochorous plant species, by comparing the seed size of each plant species to the size of the largest seed that each frugivore can swallow whole. We estimated the number of available lemur dispersers by matching the distribution of plant species to the distribution of potential dispersers. We found that, out of the 3018 studied endozoochorous plant species, two species have experienced the complete extinction of their main dispersers while 487 species suffer from the local extinction of their suitable dispersers. A limited number of dispersers could be one of the main reasons why most of these plant species are now on the edge of extinction

Phylogeny, character evolution and taxonomic revision of Causonis, a segregate genus from Cayratia (Vitaceae)

Causonis (Vitaceae) is widely distributed in the tropical, sub-tropical and temperate regions from Asia to Australia. The genus was established by Rafinesque in 1830 but included under Cayratia by Gagnepain in 1911. Generic status of Causonis was restored in 2013, but circumscription of the genus and its species remained poorly understood. Here, we sample 92 accessions of Causonis to reconstruct the phylogenetic relationships within the genus using four chloroplast loci (atpB-rbcL, trnC-petN, trnH-psbA, trnL-F) and three nuclear loci (AS1, At103, ITS). Both the chloroplast and nuclear data support the monophyly of Causonis, and relationships among major clades of the genus are well-supported based on the chloroplast data. The first diverged clade consists of two species both endemic to Australasia. Evolutionary trends of eight morphological characters are tested through ancestral character state reconstruction using the chloroplast dataset. We recognize 16 species and 4 varieties in Causonis, including two new species: C. australasica sp. nov. and C. glauca sp. nov. We herein make 10 new combinations for eight species and two varieties. The widespread Causonis japonica is also redefined based on morphological and molecular evidence