Reichardt 1985 Category: Symmetrical biraphid
BASIONYM: Navicula cryptocephala f. terrestris Lund 1946
Contributor: Loren Bahls - June 2012
Length Range: 22-38 µm
Width Range: 4.8-6.9 µm
Striae in 10 µm: 14-18
Valves are lanceolate with rounded, unprotracted to weakly subrostrate apices. The axial area is narrow. The central area is transpically expanded and asymmetric. The raphe is filiform and straight, with weakly expanded proximal ends. Striae are curved and radiate near the valve middle, becoming straight and parallel to weakly convergent near the apices. Striae in the central area are irregularly shortened. Areolae in the striae are fine and difficult to resolve in LM.
This widespread, but little known and difficult to identify taxon, lacks distinguishing features and has characteristics of several other Navicula species. Correct identification requires consideration of all morphological characters.
Basionym: Navicula cryptocephala f. terrestris
Author: Lund 1946
Length Range: 13-23 µm
Width Range: 4-6 µm
Striae in 10 µm: 15-20
Valves (13-23 µ l.; 4-6 µ br.) elliptic-lanceolate to lanceolate, margins typically convex (Fig. 9 H-L), but occasionally almost parallel centrally (Fig. 9 P, Q); one margin may be flattened centrally while the other is weakly convex, so that the valve has a cymbelloid appearance (Fig. 9 N, O, R, S). Apices sharply (Fig. 9 L) or obtusely (Fig. 9 N, O, R-U) rounded, sometimes weakly rostrate (Fig. 9 P, Q, U-W). Axial area narrow, central area transapically dilated. Branches of the raphe straight. Striae (15-20 in 10 µ) curved and radial except near the apices, where they are straight and parallel to weakly convergent.
Lange-Bertalot, H. (2001). Navicula sensu stricto, 10 genera separated from Navicula sensu lato, Frustulia. Diatoms of Europe 2: 1-526.
Lund, J.W.G. (1946). Observations on soil algae. I. The ecology, size and taxonomy of British soil diatoms. Part 2. The New Phytologist 45(1): 56-110.
Reichardt, E. (1985). Diatomeen an feuchten Felsen des südlichen Frankenjuras. Ber. Bayer. Bot. Ges. 56: 167-187.
Navicula lundii is widely distributed in moist soils and wet habitats, such as walls and seeps. In the Northwest U.S., these habitats occur in all states and ecoregions and typically have alkaline waters with average to moderately elevated dissolved solids (see table below). Small numbers of N. lundii are also present in headwater streams and along lake shores that are subject to seepage and erosion. Here it is probably an incidental floristic component.
Abundance-weighted means of selected water quality variables measured concurrently with the collection of samples containing Navicula lundii.
Credit/Source: Montana Diatom Database
Charlie Creek, Richland County, Montana: home of Navicula lundii.
Credit/Source: Loren Bahls