Lichens are symbiotic associations resulting from interactions among fungi (primary and
secondary mycobionts), algae and/or cyanobacteria (primary and secondary photobionts) …

The∼ 26 definitions of species often yield different numbers of species and disparate
groupings, with financial, legal, biological and conservation implications. Using conservation …

The species problem has triggered the publication of an almost infinite number of theoretical
and practical studies, including quite a number of books. I should, therefore, perhaps briefly …

It has recently become clear that several human lineages coexisted with Homo sapiens
during the late Middle and Late Pleistocene. Here, we report an archaic human fossil that …

A highly diverse ciliate community was found in 73 samples from terrestrial and
semiterrestrial habitats of Namibia, Southwest Africa, one of the world's driest countries. The …

The ability to discriminate between species using barcoding loci has proved more difficult in
plants than animals, raising the possibility that plant species boundaries are less well …

Subspecies lie at the interface between systematics and population genetics, and represent
a unit of biological organization in zoology that is widely used in the disciplines of taxonomy …

The US Endangered Species Act (ESA) allows listing of subspecies and other groupings
below the rank of species. This provides the US Fish and Wildlife Service and the National …

Many botanists doubt the existence of plant species,,,,, viewing them as arbitrary constructs
of the human mind, as opposed to discrete, objective entities that represent reproductively …

Herbarium collections constitute permanent and often well-documented records of the
distribution of taxa through space and time. Since their creation, their uses have dramatically …