Evolution of sexual systems and regressive evolution in Riccia.

The genus Riccia is the most speciose of the Marchantiopsida, the complex thalloid liverworts. In contrast to the predicted ancestral liverwort and the majority of extant liverworts that are dioicous, most Riccia species are monoicous. Both the gametophyte and the sporophyte generations have undergone regressive evolution in Riccia, with the sporophyte lacking many adaptations for spore dispersal.

Ancient reticulation, incomplete lineage sorting and the evolution of the pyrenoid at the dawn of hornwort diversification.

Background And Aims: Resolving the phylogeny of hornworts is critical in understanding the evolution of key morphological characters that are unique to the group, including the pyrenoid. Extensive phylogenomic analyses have revealed unexpected complexities in the placement of Leiosporoceros, the previously identified sister taxon to other hornworts. We explore the role of incomplete lineage sorting (ILS) and ancient reticulation in resolving interrelationships and understanding the diversification and evolutionary processes within hornworts.

Re-assessment of type material of Broth. and descriptions of four new taxa (Bryophyta, Plagiotheciaceae) from Australasia.

A re-examination of the original collection of described by Brotherus in 1916 indicated that this material is not homogeneous. Re-examination of the diagnosis of this species and morphological analysis supports that two separate taxa should be distinguished - Plagiotheciumnovae-seelandiaevar.novae-seelandiae and P.

The evolution and biogeographic history of epiphytic thalloid liverworts.

Among liverworts, the epiphytic lifestyle is not only present in leafy forms but also in thalloid liverworts, which so far has received little attention in evolutionary and biogeographical studies. Metzgeria, with about 107 species worldwide, is the only genus of thalloid liverworts that comprises true epiphytes. In the present study, we provide the first comprehensive molecular phylogeny, including estimated divergence times and ancestral ranges of this genus.

Variational scaling law for atmospheric propagation.

A new scaling law model for propagation of optical beams through atmospheric turbulence is presented and compared to a common scalar stochastic waveoptics technique. This methodology tracks the evolution of the important beam wavefront and phasefront parameters of a propagating Gaussian-shaped laser field as it moves through atmospheric turbulence, assuming a conservation of power. As with other scaling laws, this variational technique makes multiple simplifying assumptions about the optical beam to capture the essential features of interest, while significantly reducing the computational cost of calculation.