Surirellales

Valve view of the pennate diatom, Cymatopleura solea (Brébisson) W. Smith 1851. Valves are elliptical with a central waist and bluntly pointed apices. The valve surface is marked with several transverse undulations best seen in girdle view; striae and undulations are not interrupted in the median axis. Raphe are marginal. Very short costations appear as beading around the edge of the valve. There is a single lobulated plastid one half of which lies along the inner surface of the epivalve and the other along the inner surface of the hypovalve. Collected from the benthos of a freshwater pond near Boise, Idaho, January 2005. DIC.

Optical section (girdle view) of the pennate diatom, Cymatopleura solea (Brébisson) W. Smith 1851. Valves are elliptical with a central waist and bluntly pointed apices. The valve surface is marked with several transverse undulations best seen in girdle view (seen well in this image). Striae and undulations are not interrupted in the median axis. Raphe are marginal. Very short costations appear as beading around the edge of the valve. The central nucleus is seen in this image. There is a single lobulated plastid one half of which lies along the inner surface of the epivalve and the other along the inner surface of the hypovalve. Collected from the benthos of a freshwater pond near Boise, Idaho, January 2005. DIC.

Optical section (girdle view) of the pennate diatom, Cymatopleura solea (Brébisson) W. Smith 1851. Valves are elliptical with a central waist and bluntly pointed apices. The valve surface is marked with several transverse undulations best seen in girdle view; striae and undulations are not interrupted in the median axis. Raphe are marginal. Very short costations appear as beading around the edge of the valve. There is a single lobulated plastid one half of which lies along the inner surface of the epivalve and the other along the inner surface of the hypovalve (seen well in this image). Collected from the benthos of a freshwater pond near Boise, Idaho, January 2005. DIC.

Optical section (valve view) of the pennate diatom, Cymatopleura solea (Brébisson) W. Smith 1851. Valves are elliptical with a central waist and bluntly pointed apices. The valve surface is marked with several transverse undulations best seen in girdle view; striae and undulations are not interrupted in the median axis. Raphe are marginal. Very short costations appear as beading around the edge of the valve. There is a single lobulated plastid one half of which lies along the inner surface of the epivalve and the other along the inner surface of the hypovalve (seen well in this image). Collected from the benthos of a freshwater pond near Boise, Idaho, January 2005. DIC.  

Diatom with strongly developed internal intrusions of the frustule, girdle view. 

Empty frustules by phase contrast microscopy. Generic identity needs to be confirmed.

Its the thing on the left (the thing on the right is a sand grain). A rather asymmetrical and often twisted pennate diatom, which in this case has valves that are a bit dish-like and are very often twisted. Frustule only, differential interference contrast optics.

A rather asymmetrical and often twisted pennate diatom, which in this case has valves that are a bit dish-like. This species is common in Alkaline Lake. Frustule and residue of cytoplasm, differential interference contrast optics.

A rather asymmetrical and often twisted pennate diatom, which in this case has valves that are a bit dish-like. This species is common in Alkaline Lake. Frustule and fragments of cytoplasm, phase contrast optics. 

A rather asymmetrical and often twisted pennate diatom, which in this case has valves that are a bit dish-like. Girdle bands are splitting away from the frustule. This species is common in Alkaline Lake. Frustule only, phase contrast optics.