• Category
  • Length Range
    33-39 µm
  • Width Range
    4.9-5.7 µm
  • Striae in 10 µm
  • Reported As
    Navicula heimansii (Van Dam and Kooyman 1982)



Valves are narrowly lanceolate with acutely rounded, subtly protracted apices. Valves are lightly silicified and features tend to be faint and difficult to resolve. The raphe is filiform. Proximal raphe ends are very close and deflected to the primary side. The axial area is very narrow. The central area is small, transversely widened, and asymmetrical with irregular borders. Striae are curved and strongly radiate near the valve middle, becoming strongly convergent near the apices. Areolae are very close together and cannot be distinguished in LM.


Navicula leptostriata has been recorded from eight streams and small lakes in the northern Rocky Mountains, where it is typically associated with Navicula notha. The mean pH at these locations is 7.5 and the mean specific conductance is 154 µS/cm.

Summit  Lake  General
Credit: Photo courtesy of Barb Johnston, Parks Canada.
Summit Lake, Waterton Lakes National Park, Alberta: home of Navicula leptostriata.

Original Description

N. leptostriata nov. sp., pl. II, fig. 25. The frustule narrow lanceolate with slightly prominent ends. Length 18.5-31.5 µ, 4-5 µ. Axial area very narrow, central area small, round. Transversal striae very faint, radial, convergent towards the apex, 20-23 in 10 µ, 25 towards the apex.

Østrup (1910) found a species in Madum Sø which, on examining his original slide, I have convinced myself is identical with N. leptostriata. Østrup placed his find to N. nuda Pant. in Pantocsek 1886-93 II p. 51; table VI, fig. 108. In my opinion N. leptostriata has nothing to do with this one. N. nuda is somewhat larger, 37.5 µ long and 7 µ wide and lacks striae. The striae on N. leptostriata are very faint in styrax but more distinct in realgar. N. nuda is also stated as having been found in brackish water.

Dominant in Madum Sø, in smaller numbers in Skørsø, Grovsø and Øjesø. pH: 5.0-6.8, acidophilous.

  • Author
    E.G.Jørg. 1948
  • Length Range
    18.5-31.5 µm
  • Width
    4-5 µm
  • Striae in 10µm
    20-23, 25 towards the apex

Original Images

Navicula Leptostriata Orig Desc Plate
Navicula Leptostriata Orig Desc Text

Citations & Links

Cite This Page

Bahls, L. (2012). Navicula leptostriata. In Diatoms of North America. Retrieved June 23, 2024, from https://diatoms.org/species/navicula_leptostriata


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Navicula leptostriata 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.