Observations on new and rare species of freshwater diatoms from Cape Cod, Massachusetts, USA
The freshwater diatom flora of Cape Cod, Massachusetts, USA, was recently described using surface sediments from 56 largely glacial kettle lakes scattered over the narrow peninsula. During our examination we had the opportunity to study seven rare and interesting taxa with light (LM) and scanning electron microscopy (SEM). Two of these organisms, Neidium statuarium Hamilton & Siver sp.nov. and Stenopterobia pseudodelicatissima Siver & Hamilton sp.nov., are described as new species. Two new combinations, along with emended descriptions based on SEM, are provided for Nupela vitiosa (Schimanski) Siver & Hamilton comb.nov. and Tryblionella scalaris (Ehrenberg) Siver & Hamilton comb.nov. Morphological details of three additional and rare species, Neidium fasiatum Østrup, Neidium sp., and Tryblionella plana var. fennica (Hustedt) Simola are also provided. The relationships of each taxon to other similar species are discussed.Key words: Cape Cod, Neidium, new species, Nupela, Stenopterobia, Tryblionella.