Topic
Afrocarum
About: Afrocarum is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 130 citations.
Papers
TL;DR: The phylogenetic analyses showed that Afrocarum and the African and St. Helena species of Sium were nested within Berula forming the Berula s.l. clade, and suggested that the biogeographic pattern of this group resulted from simple vicariance and eventual migration to adjacent areas rather than from long-distance dispersal.
Abstract: The biogeographic history of Sium sensu lato (s.l.) (including Sium sensu stricto [s.s.], Afrocarum, and Berula) was inferred using a nuclear rDNA ITS sequence phylogeny and dispersal-vicariance analysis. One hundred accessions were analyzed, including 86 specimens of Sium s.l., representing all taxa throughout their geographical range. The phylogenetic analyses showed that Afrocarum and the African and St. Helena species of Sium were nested within Berula forming the Berula s.l. clade. The remaining species of Sium constituted a weakly supported Sium s.s. clade. The cultivated S. sisarum is closely related to the western Asian S. sisaroideum. The divergence of Sium s.s. from Berula s.l., estimated under the assumption of a molecular clock and using a substitution rate of 0.61% per million years, took place around 10.4 million years ago. Dispersal-vicariance analysis suggested that the biogeographic pattern of this group resulted from simple vicariance and eventual migration to adjacent areas rather than from long-distance dispersal. The ancestral area of Sium s.l. was probably western Palearctic. The dispersal of Berula to North America occurred ca. 3 million years ago, possibly by island hopping. The migration of S. suave to North America took place ca 0.6 million years ago through Beringia.
70 citations
TL;DR: Representatives of eight genera native to North America comprise a monophyletic group, and results from relative rate tests suggest that this lineage is evolving much faster than any other major clade recognised within the tribe.
60 citations
TL;DR: Results of Bayesian analysis and maximum parsimony analyses of partitioned and combined data revealed that the Sium alliance is strongly supported as monophyletic.
Abstract: Previous studies of the Sium alliance within Apiaceae tribe Oenantheae, based only on nrDNA ITS sequences, revealed that the genera Sium and Berula may not be monophyletic. To confirm issues of relationships and implement nomenclatural changes, we obtained additional ITS sequences as well as independent data from the cpDNA rps16-5'trnK( UUU ) region which includes the rps16 intron and the spacer region between genes rps16 and 5'trnK. We examined 78 accessions of tribe Oenantheae including representatives of all 23 species of the Sium alliance (Afrocarum, 1 sp.; Apium pro partel/Helosciadium, 5 spp.; Berula, 1 sp.; Cryptotaenia, 4 spp.; Sium, 12 spp.). Results of Bayesian analysis and maximum parsimony analyses of partitioned and combined data revealed that the Sium alliance is strongly supported as monophyletic. Within this clade, four major subclades are resolved. Three of these subclades comprise species that were traditionally placed in Cryptotaenia, HelosciadiumlApium pro parte, and Sium s.str. (9 spp.). A restitution of the genus Helosciadium, including all Eurasian species ofApium with the exception of A. graveolens, the generitype, is supported by both molecular data and morphology. The fourth subclade, Berula sensu lato, encompasses all representatives of a widely distributed B. erecta, a monotypic African Afrocarum, and three members of Sium from Africa (S. repandum) and Saint Helena (S. bracteatum, S. burchellii). The Sium species from Saint Helena form a sister group to African representatives of B. erecta. The Berula sensu lato clade is recognized at the generic level and these four African/Saint Helena species are transferred into Berula. African and North American populations of B. erecta are distinct from their Eurasian relatives and are therefore proposed to be treated as separate species (B. thunbergii and B. incisa, respectively).
56 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2009 | 1 |
| 2006 | 1 |
| 2004 | 1 |