• Category
  • Length Range
    24-64 µm
  • Width Range
    2-3 µm
  • Striae in 10 µm
    Not visible in the light microscope



Valves are delicate, narrowly lanceolate with rostrate and subcapitate apices. Keel strongly excentric, fibulae 15-17 in 10 µm and of differing sizes. The striae are not resolvable in the light microscope.

This specimen is easily overlooked in sample due to their delicate nature. Found in low numbers throughout the Pacific Northwest.


Original Description

Valvae anguste lanceolatae apicibus rostratis subcapitatis, 40-64 µ longae, 2-3 latae; carina valde excentrica punctis carinalibus 15-17 in 10 µ striae transapicales inconsipicuae

  • Author
    Sovereign 1958
  • Length Range
    40-64 µm
  • Width
    2-3 µm
  • Striae in 10µm
    striae inconspicuous

Original Images

Nitzschia Exilis Orig Illus2
Nitzschia Exilis Orig Desc

Cite This Page

Kociolek, P. (2011). Nitzschia exilis. In Diatoms of North America. Retrieved May 18, 2024, from https://diatoms.org/species/nitzschia_exilis


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