The Apocynaceae comprise approximately 5,000 species and are widely distributed. The family belongs to the Gentianales and can be easily recognized by the presence of latex and a style-head derived ...from the fusion of two carpels at the apex of the styles. The largest subfamily in Apocynaceae is Asclepiadoideae. Treated as the Asclepiadaceae for almost two centuries, it comprises about 3,000 species and is defined by stamens with bisporangiate anthers and pollen transferred in specialized units called pollinaria. Since the 19th century, floristic studies and taxonomic monographs have significantly contributed to the taxonomy of Brazilian Asclepiadoideae. Nevertheless, advances in understanding the internal relationships in the subfamily were not done until this millennium, with the popularization of phylogenetic studies based on molecular data and powerful computer analyses. Advances in the systematics of Apocynaceae have provided new interpretations on the morphological evolution and biogeography of the family and have led to important changes in its classification. Nevertheless, several taxonomic rearrangements are still needed and it can be said that the taxonomy of Apocynaceae is "under construction". In this article, the major taxonomic changes in the family are reviewed, with special attention given to the systematics of Neotropical groups. A cladogram of the Apocynaceae is presented, which highlights the phylogenetic position of the Brazilian genera and their diversity in number of native species. The main studies and the diversity of Asclepiadoideae in Brazil are summarized and perspectives for future research on the subfamily are presented.
Plants have demonstrated tremendous resilience through past mass extinction events. However, anthropogenic pressures are rapidly threatening plant survival. To develop our understanding of the impact ...of environmental change on plant ecology and evolution and help solve the current biodiversity crisis, BMC Ecology and Evolution has launched a new article Collection titled "Plants under Pressure".
Apresentamos aqui o levantamento das Apocynaceae de Vitória da Conquista, Bahia, Brasil. São reconhecidos 18 gêneros e 26 espécies nativas, incluindo 11 ocorrências novas para o município: Asclepias ...curassavica, Aspidosperma polyneuron, Blepharodon ampliflorum, Ditassa grandiflora, D. lenheirensis, Himatanthus bracteatus, Ibatia ganglinosa, Macropharynx peltata, Oxypetalum arachnoideum, Petalostelma dardanoi e Skytanthus hancorniifolius. Além disso, a identificação de Forsteronia thyrsoidea é atualizada para F. nitida.
The MOG clade is one of the four neotropical lineages of the subfamily Asclepiadoideae (Apocynaceae), and its core group is formed by the subtribes Metastelmatinae, Oxypetalinae, Gonolobinae, ...Tassadiinae and Topeinae, consisting of about 935 species and 63 genera. These subtribes form well-supported and morphologically distinguishable clades, but the relationships among them are yet to be resolved. Metastelmatinae is composed of approximately 300 species and 12 genera with complex circumscriptions. There is no agreement regarding the sequence of phylogenetic events at the beginning of the Metastelmatinae evolution.
Petalostelma
stands out for being a genus frequently assigned to the basal grade of Metastelmatinae. In this study, we evaluated the circumscription of
Petalostelma
, its phylogenetic position in Metastelmatinae and the relationships between the subtribes of the MOG core group, thus offering an overview of the initial diversification of Metastelmatinae. Our results support the monophyly of
Petalostelma
and a basal grade sequentially formed by
Blepharodon
s.s.,
Petalostelma
,
Barjonia
and
Minaria
within Metastelmatinae; however, alternative hypotheses in which the positions of
Petalostelma
and
Barjonia
are interchanged cannot be rejected. The sister clades Metastelmatine–Gonolobinae and Oxypetalinae–Tassadiinae are the most likely within the MOG core group, although without statistical significance. We also present a taxonomic revision of
Petalostelma
in Brazil, including complete morphological descriptions, an identification key, illustrations, distribution maps, assessments of the conservation status and taxonomic comments for the nine species recognized in the country, including a new species from eastern Brazil,
P. atlanticum
, endemic to Espírito Santo and critically endangered.
In a world where changes in land cover and climate happen faster than ever due to the expansion of human activities, narrowly distributed species are predicted to be the first to go extinct. Studies ...projecting species extinction in tropical regions consider either habitat loss or climate change as drivers of biodiversity loss but rarely evaluate them together. Here, the contribution of these two factors to the extinction risk of narrowly distributed species (with ranges smaller than 10,000 km
) of seed plants endemic to a fifth-order watershed in Brazil (microendemics) is assessed. We estimated the Regional Climate Change Index (RCCI) of these watersheds (areas with microendemics) and projected three scenarios of land use up to the year 2100 based on the average annual rates of habitat loss in these watersheds from 2000 to 2014. These scenarios correspond to immediate conservation action (scenario 1), long-term conservation action (scenario 2), and no conservation action (scenario 3). In each scenario, areas with microendemics were classified into four classes: (1) areas with low risk, (2) areas threatened by habitat loss, (3) areas threatened by climate change, and (4) areas threatened by climate change and habitat loss. We found 2,354 microendemic species of seed plants in 776 areas that altogether cover 17.5% of Brazil. Almost 70% (1,597) of these species are projected to be under high extinction risk by the end of the century due to habitat loss, climate change, or both, assuming that these areas will not lose habitat in the future due to land use. However, if habitat loss in these areas continues at the prevailing annual rates, the number of threatened species is projected to increase to more than 85% (2,054). The importance of climate change and habitat loss as drivers of species extinction varies across phytogeographic domains, and this variation requires the adoption of retrospective and prospective conservation strategies that are context specific. We suggest that tropical countries, such as Brazil, should integrate biodiversity conservation and climate change policies (both mitigation and adaptation) to achieve win-win social and environmental gains while halting species extinction.
Cryptostegia grandiflora
and
C. madagascariensis
(Apocynaceae) are the only two species of this Madagascan plant genus. Both have been transported around the world as ornamentals due to their ...attractive flowers and based on a perceived potential as sources of rubber – hence, the common name rubber vine – because of their copious latex, which also contains toxic cardiac glycosides. As a result of their vigorous growth and ability to climb over and smother vegetation, both species have become invasive, posing an actual or potential threat to native ecosystems in many tropical and sub-tropical countries, as well as to human and animal health. Classical biological control (CBC), or the introduction of co-evolved natural enemies to control an invasive alien species in its exotic range, has successfully been used to tackle
C. grandiflora
in northern Queensland, Australia. This strategy is currently being evaluated for its suitability to manage
C. madagascariensis
in north-eastern Brazil using the same Madagascan rust fungus,
Maravalia cryptostegiae
, released as a CBC agent in Australia. For CBC to be successful, it is critical to understand the taxonomy of the invader as well as the origin(s) of its weedy biotype(s) in order to select the best-matched co-evolved natural enemies. Based on an exhaustive search in published and unpublished sources, we summarise the taxonomy and uses of these rubber vines, follow their historical movements and track their earliest records and current weed status in more than 80 countries and territories around the world.
Hemipogon s. str. (Apocynaceae: Asclepiadoideae) currently consists of three species sharing an erect herbaceous habit, narrow leaves and corona-less flowers with urceolate, internally bearded ...corolla, that are mainly distributed in savannahs of the Cerrado biodiversity hotspot, South America. Here, we describe and illustrate a new species of Hemipogon, H. trilobatus Bitencourt & Rapini sp. nov., from an open savannah in Chapada dos Veadeiros, Central Brazil. Hemipogon trilobatus sp. nov. differs from the other species of the genus mainly by the presence of a reduced staminal corona with 3-lobed lobes, but also by opposite leaves and triangular anthers. Distribution and habitat data, as well as a key and a comparative table to distinguish the four species currently accepted in Hemipogon s. str., are provided. Based on criteria B2ab(i,ii,iii,iv) of the International Union for Conservation of Nature (IUCN), the species is provisionally assessed as Critically Endangered.
Apocynaceae (the dogbane and milkweed family) is one of the ten largest flowering plant families, with approximately 5,350 species and diverse morphology and ecology, ranging from large trees and ...lianas that are emblematic of tropical rainforests, to herbs in temperate grasslands, to succulents in dry, open landscapes, and to vines in a wide variety of habitats. Despite a specialized and conservative basic floral architecture, Apocynaceae are hyperdiverse in flower size, corolla shape, and especially derived floral morphological features. These are mainly associated with the development of corolline and/or staminal coronas and a spectrum of integration of floral structures culminating with the formation of a gynostegium and pollinaria—specialized pollen dispersal units. To date, no detailed analysis has been conducted to estimate the origin and diversification of this lineage in space and time. Here, we use the most comprehensive time-calibrated phylogeny of Apocynaceae, which includes approximately 20% of the species covering all major lineages, and information on species number and distributions obtained from the most up-to-date monograph of the family to investigate the biogeographical history of the lineage and its diversification dynamics. South America, Africa, and Southeast Asia (potentially including Oceania), were recovered as the most likely ancestral area of extant Apocynaceae diversity; this tropical climatic belt in the equatorial region retained the oldest extant lineages and these three tropical regions likely represent museums of the family. Africa was confirmed as the cradle of pollinia-bearing lineages and the main source of Apocynaceae intercontinental dispersals. We detected 12 shifts toward accelerated species diversification, of which 11 were in the APSA clade (apocynoids, Periplocoideae, Secamonoideae, and Asclepiadoideae), eight of these in the pollinia-bearing lineages and six within Asclepiadoideae. Wind-dispersed comose seeds, climbing growth form, and pollinia appeared sequentially within the APSA clade and probably work synergistically in the occupation of drier and cooler habitats. Overall, we hypothesize that temporal patterns in diversification of Apocynaceae was mainly shaped by a sequence of morphological innovations that conferred higher capacity to disperse and establish in seasonal, unstable, and open habitats, which have expanded since the Eocene-Oligocene climate transition.
The Eriocaulaceae are easily recognized because of the small unisexual flowers in long-pedunculate heads and spiraperturate pollen grains. Their monophyly has never been disputed but internal ...relationships within the family have not been broadly explored and genera are typically distinguished by few floral characters. Here, we present the first comprehensive phylogenetic study of Eriocaulaceae based on individual and combined molecular datasets, including the plastid psbA-trnH and trnL-F and the nuclear ITS. Results are largely congruent among DNA regions and support the internal dichotomy between the two subfamilies: Eriocauloideae and Paepalanthoideae. Eriocaulon and Leiothrix are strongly supported as monophyletic, whereas Paepalanthus, Blastocaulon, and Syngonanthus are not monophyletic. The phylogenetic nature of Actinocephalus is not resolved and Lachnocaulon, Mesanthemum, Philodice, Rondonanthus, and Tonina (monospecific) are represented in our analyses by a single species each. Based on our results, we suggest two principal generic realignments in the family. The first is the division of Syngonanthus in two genera: Syngonanthus s.str., including Philodice (conserving the former name against the latter), and Comanthera, which is being reinstated to include two sections segregated from Syngonanthus: S. sect. Eulepis and S. sect. Thysanocephalus. The second realignment suggested is the amalgamation of Actinocephalus, Blastocaulon, Lachnocaulon, and Tonina into Paepalanthus s.l. Three 'stat. nov.' within Paepalanthus are published (P. ser. Leptocephali, P. ser. Rosulati, and P. ser. Dimeri).
Abstract A new species of Apocynaceae, Ruehssia quirinopolensis, endemic to Serra da Confusão do Rio Preto and Serra da Igrejinha, Quirinópolis, state of Goiás, Brazil, is described and illustrated. ...It resembles R. rupestris, differing by the white corolla, adaxially villose and with a longer tube, and by its corona lobes with the upper portion lanceolate. Besides a distribution map for the new species, we provide a key to identify the nine species of Ruehssia that occur in Goiás. Ruehssia quirinopolensis is assessed here as Critically Endangered (CR).
Resumo Uma nova espécie de Apocynaceae, Ruehssia quirinopolensis, endêmica da Serra da Confusão do Rio Preto e Serra da Igrejinha, Quirinópolis, estado de Goiás, Brasil, é descrita e ilustrada. Ela se assemelha a R. rupestris, diferindo, pela corola branca, adaxialmente vilosa e com tubo mais longo, e pelos lobos da corona com a porção superior lanceolada. Além de um mapa de distribuição para a nova espécie, apresentamos uma chave para identificar as nove espécies de Ruehssia que ocorrem em Goiás. Ruehssia quirinopolensis é avaliada aqui como Criticamente em Perigo (CR).
PDF
