• Category
  • Length Range
    23-27 µm
  • Width Range
    4.5-5.5 µm
  • Striae in 10 µm
    about 40



Valves are linear with slightly convex margins and capitate apices. The axial area is linear and very narrow, widening slightly near the central area. The central area is a broad stauros shaped like a bow tie. The raphe is filiform and straight, with slightly expanded proximal ends. Striae are slightly curved and strongly radiate. Areolae are difficult to resolve in LM and number near 40 in 10 µm.


Stauroneis agrestis has been recorded from small lakes, ponds and streams in the northern Rocky Mountains where mean pH is 6.6 and mean conductance is 9 µS/cm. Van de Vijver et al. (2004) report S. agrestis as an aerophile that is widespread in the Arctic. Werum and Lange-Bertalot (2004) report it from springs in Germany and the central Alps.

Atlantic  Pond 1
Credit: Loren Bahls
Atlantic Pond, Atlantic Creek drainage, Glacier National Park, MT: home of Stauroneis agrestis.

Original Description

  • Author
    J.B.Petersen 1915

Cite This Page

Bahls, L. (2012). Stauroneis agrestis. In Diatoms of North America. Retrieved July 22, 2018, from https://diatoms.org/species/stauroneis_agrestis


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