Gustav Fischer Verlag, Stuttgart

Aulacoseira validating

Although some populations of A. This also shows from the subfossil records and present distribution of A. Material from the type location is also present in other collections, e.

This also shows

Although the present knowledge of A. The development of a true riverine phytoplankton assemblage along a lake-fed lowland river. Evidence for the pollution of Loch Ness from the analysis of its recent sediments. Spatio-temporal distribution of Aulacoseira granulata and A. At present we assume that no type material is available.

Their length does not exceed ca. In the ultra-oligotrophic Loch Ness it appeared only in the last few decades Jones et al. Introduction Aulacoseira species are important diatoms in a range of freshwater systems throughout the world. Unless the variation of rimoportula features is much greater in A.

Cambridge, Cambridge University Press, pp. Typical more delicate Aulacoseira subborealis is also present in Lac Chauvet, without intergradation between both. At its edge with the valve face, the mantle is more or less rounded off. In the Dutch part of the River Maas, A.

The genus Melosira from soft-water lakes with special reference to northern Michigan, Wisconsin and Minnesota. The distribution of Cyclostephanos dubius in Norfolk. Recent observations by the authors indicate that Aulacoseira subarctica f. Other literature reports also indicate that its status is in need of further clarification. Fine areolae are present on the entire valve face, where they are often placed in a more or less radial pattern in continuation of the rows of areolae on the mantle.

Although some populations

The spatial distribution of both species suggests that A. Probably due to the limited spine length only ca. Koeltz Scientific Books, Koenigstein, Germany.

The areolae become progressively smaller towards the centre. Some variation is observed in the degree of silicification of the frustule. Distribution of certain diatom taxa in the waterbodies of Cumbria, U. The other cells, however, have valves that are areolated as in A. This series of transmission electron micrographs shows the major valve characteristics allowing discrimination against other Aulacoseira species.