Since the 19th century several researchers including European and
American diatomists have described new diatom species from the inland
waters of the United States. However, the characterisation of diatom
flora of these territories is still in the period of
discovery. Becoming acquainted with the diatom taxa living in these
waterbodies and understanding their ecological characteristics is
important because diatoms can be applied in water quality monitoring
for both running and standing waters.
In the National Lakes Assessment program a thousand lakes of the
United States were evaluated based on benthic diatoms from sediment
core samples. In this book the authors present the diatom taxa of
sediments from more than 200 lakes across the Western United States
(12 states from North Dakota to California) investigated in the NLA
program. Sixty-two taxa are described including 50 species (in 23
genera, mainly raphid pennates) new to science. Two new combinations
are offered and one species (Navicula caldwellii) is reported for the
first time from the USA.
The distinction between newly described and previously established
taxa may appear to be slight. The reason for the use of such
fine-grained taxonomic approach is that the authors took notice of the
cases of the so-called “pseudo cryptic species” in diatoms. This term
means species discovered an originally single, morphology-defined
species using other (e.g. molecular) methods and their distinctive
morphological features were defined after that.
The authors described the most new taxa from Oregon State due to the
ultra pristine environments of the Cascade Mountains holding relict
flora. This result shows the speciality of the Pacific Northwest of
the United States. However, the diversity in the neighbouring
California was much lower because of the many perturbed habitats.
The descriptions of taxa are included in the framework of a regular
research paper involving introduction, materials and methods, results
and discussion as well as general conclusion sections. In the
taxonomic part light and in almost all cases scanning electron
microscopic description in English, information on distribution across
the study area and/ or comparison with similar taxa are provided for
each taxon. For new species description in Latin, holotype and type
locality, for new combinations basionym are also given. One taxon
(Amphora sp.) could be identified only to genus level.
The descriptions of taxa are illustrated with good quality light and
scanning electron microscopic photographs arranged on eighty
plates. Highlighting certain distinguishing features these
illustrations can help the understanding of the delineations.
Overall, this volume provides a good insight into the diatom flora of
the United States. It can be useful for everyone interested in the
Acta Botanica Hungarica 56 (3-4)