GENERA starting with "T"

Araphid - Tabellaria valves are elongate with capitate ends. The valves are generally wider at the center than at the ends. A rimoportula is present in the center of the valve face. Septae are present on the numerous copulae (girdle bands). Pseudoseptae may also be present. Cells form zig-zag colonies joined by mucilage pads secreted from apical porefields. Tabellaria is considered a close relative of Oxyneis. The two genera...

Araphid - The species in Tabularia are robust and "needle-like", with a broad sternum. The striae are relatively broad and composed of complex areolae. An apical porefield is present at each pole. Each valve possesses a single rimoportula, positioned near one pole. Tabularia includes species that were formerly considered in Synedra, including S. tabulata and S. fasciculata. Members of the genus are found in marine and brackish...

Centric - Terpsinoë is a multipolar, 'centric' diatom. The frustules are heavily silicified and elongate, with strongly undulate margins. Porefields are located at the valve apices. Internal, heavily silicified transverse costae are present. In girdle view, the transverse costae appear to form the shape of musical notes. Rimoportulae are positioned near the center of the valve face. Terpsinoë grows commonly in tropical and...

Araphid - Frustules of Tetracyclus are heavily silicified. The valves are elliptical to elongate, and often capitate. The valve margins may be expanded centrally. The valve face is flat, while the valve mantle is relatively high. Striae are uniseriate and continue over the costae. Valves may have up to two rimoportulae, positioned near the valve center. Cells form zig-zag colonies joined by mucilage pads. Tetracyclus is...

Centric - The valve face of most freshwater species of Thalassiosira is flat, although some are tangentially undulate. The mantle is usually relatively narrow. Striae are radial and not arranged in fascicles. Marginal fultoportulae are positioned near marginal spines, or occluded processes. One to several fultoportulae are also located near the center of the valve face, often in a circular array. Species of Thalassiosira grow...

Nitzschioid - Valves are typically linear-lanceolate to elliptical in some species. Like Nitzschia, Tryblionella possesses an excentric raphe, positioned in a canal along one valve margin. The raphe systems within a frustule are positioned on opposite, in the manner of nitzschiod symmetry. The raphe canal is supported by fibulae. Valves have a distinct longitudinal undulation on the face. Although Tryblionella was described in 1853,...