A bi-organellar phylogenomic study of Pandanales: inference of higher-order relationships and unusual rate-variation patterns.

We used a bi-organellar phylogenomic approach to address higher-order relationships in Pandanales, including the first molecular phylogenetic study of the panama-hat family, Cyclanthaceae. Our genus-level study of plastid and mitochondrial gene sets includes a comprehensive sampling of photosynthetic lineages across the order, and provides a framework for investigating clade ages, biogeographic hypotheses and organellar molecular evolution. Using multiple inference methods and both organellar genomes, we recovered mostly congruent and strongly supported relationships within and between families, including the placement of fully mycoheterotrophic Triuridaceae.

Evolution of endemism on a young tropical mountain.

Tropical mountains are hot spots of biodiversity and endemism, but the evolutionary origins of their unique biotas are poorly understood. In varying degrees, local and regional extinction, long-distance colonization, and local recruitment may all contribute to the exceptional character of these communities. Also, it is debated whether mountain endemics mostly originate from local lowland taxa, or from lineages that reach the mountain by long-range dispersal from cool localities elsewhere.

Evolution of mycoheterotrophy in Polygalaceae: The case of Epirixanthes.

Premise Of The Study: The mycoheterotrophic lifestyle has enabled some plant lineages to obtain carbon from their mycorrhizal symbionts. The mycoheterotrophic genus Epirixanthes (Polygalaceae) consists of six species from tropical Asia. Although it is probably closely related to the chlorophyllous genus Salomonia and linked to arbuscular mycorrhizal fungi, lack of DNA sequence data has thus far prevented these hypotheses from being tested.

New insights in the long-debated evolutionary history of Triuridaceae (Pandanales).

The mycoheterotrophic plant family Triuridaceae (Pandanales) is hypothesized to be an old family, mainly based on its pantropical distribution. The existence of fossils from the Upper Cretaceous, assigned to Triuridaceae may form additional support for a great age of the family, although the affinity of these fossils to Triuridaceae is questioned. Although the circumscription of Triuridaceae has never been problematic, probably due to its distinct morphological characters, its systematic relationship has been under debate since the family was described around 1840.

Phylogenetic relationships of the mycoheterotrophic genus Voyria and the implications for the biogeographic history of Gentianaceae.

Premise Of The Study: The angiosperm family Gentianaceae comprises over 1700 species in 91 genera. Gentianaceae are distributed worldwide, but most species occur in temperate zones. Phylogenetic studies demonstrate that the family consists of six monophyletic tribes.