Bory de Saint-Vincent 1822 Category: Symmetrical biraphid
TYPE SPECIES: Navicula tripunctata (O. Müller) Bory de Saint-Vincent
Valves of Navicula tend to be elliptical to broadly-lanceolate in outline. Valve ends may be capitate, acute, rounded, or not expanded. The central sternum is thickened, and that thickening may be somewhat asymmetric. Pseudosepta may be present, or absent. The raphe is straight and filiform, or lateral in some species. The proximal raphe ends are slightly deflected to one side. The central area may be expanded, but the silica is not thickened into a fascia.
In the strict sense, Navicula Bory contains species with lineate areolae. During the mid-1900’s (primarily through the work of Hustedt), Navicula became a genus that contained a large number of unrelated lanceolate, biraphid species. Many of these unrelated species have recently been separated into new genera or replaced into the older, originally described genera.
Cite This Page:
Spaulding, S., and Edlund, M. (2008). Navicula. In Diatoms of the United States. Retrieved December 22, 2014, from http://westerndiatoms.colorado.edu/taxa/genus/Navicula