Diatoms of North AmericaDiatoms of North America

Navicula lundii

E.Reichardt 1985

Navicula Lundii Guide
  • Category
    Symmetric Biraphid
  • Length Range
    22-38 µm
  • Width Range
    4.8-6.9 µm
  • Striae in 10 µm
    14-18

Identification

Navicula lundii LM7 Navicula lundii LM6 Navicula lundii LM5 Navicula lundii LM4 Navicula lundii LM3 Navicula lundii LM2 Navicula lundii LM1
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Description

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.

Autecology

This taxon 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.

Navlundii Chem 001
Credit: Montana Diatom Database
Abundance-weighted means of selected water quality variables measured concurrently with the collection of samples containing Navicula lundii.
Charlie Creek 1
Credit: Loren Bahls
Charlie Creek, Richland County, Montana: home of Navicula lundii.

Original Description

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.

  • Basionym
    Navicula cryptocephala f. terrestris
  • Author
    Lund 1946
  • Length Range
    13-23 µm
  • Width
    4-6 µm
  • Striae in 10µm
    15-20

Original Images

Navlundii Origimag
Navlundii Origdesc

Cite This Page

Bahls, L. (2012). Navicula lundii. In Diatoms of North America. Retrieved April 20, 2024, from https://diatoms.org/species/navicula_lundii

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Navicula lundii from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.