• Category
  • Length Range
    50-101 µm
  • Width Range
    5.2-7.4 µm
  • Striae in 10 µm
  • Reported As
    Nitzschia intermedia (Krammer and Lange-Bertalot 1988)
    Nitzschia regula (Lange-Bertalot and Metzeltin 1996)



Valves are linear with short, wide, subcapitate apices. Fibulae are distinct and number 9-12 in 10 µm. The central two fibulae are equidistant and a central nodule is lacking. Striae are indistinctly punctate.


Nitzschia regula var. robusta has been found in a few cold-water and circumneutral ponds and streams with low levels of electrolytes in the Northern Rocky Mountains of Montana and Alberta. This taxon was described from samples collected in Swedish Lapland.

Paradise  Pond And  Rising  Wolf  Mountain 2
Credit: Loren Bahls
Paradise Pond below Rising Wolf Mountain, Glacier National Park, Montana: home of Nitzschia regula var. robusta.

Original Description

  • Author
    Hust. 1924

Original Images

Nitzschia Regula Var Robusta Orig Desc Text

Cite This Page

Bahls, L. (2012). Nitzschia regula var. robusta. In Diatoms of North America. Retrieved June 20, 2024, from https://diatoms.org/species/nitzschia_regula_var._robusta


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