• Category
  • Length Range
    25-45 µm
  • Width Range
    9.5-12 µm
  • Striae in 10 µm
    10-13 in the center, 14-16 at the poles



Valves are lanceolate-clavate, with a distinctly protracted, broadly rounded head-pole, a robust to linear central portion of the valve and a distinctly rounded footpole. Smaller valves are elliptical-clavate, with the headpole protracted slightly. Striae are radiate at the central portion of the valve and strongly radiate at the poles. The raphe is undulate and lateral. The axial area is narrow, widening slightly towards the central area. A small, barely circular central area with a single stigma is present. The striae have individual areolae observable with DIC or oblique light in the light microscope. Longitudinal lines are distinct near the axial area, less so at the apices. Apical pore fields are present at the footpole.

Gomphoneis eriense var. variabilis is widely distributed throughout western North America.


Original Description

  • Author
    Kociolek and Stoermer 1988

Original Images

Gvariabilis Text

Cite This Page

Kociolek, P. (2011). Gomphoneis eriense var. variabilis. In Diatoms of North America. Retrieved July 13, 2024, from https://diatoms.org/species/gomphoneis_variabilis


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Gomphoneis eriense var. variabilis 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.