Valves are clavate, with a broadly rounded headpole and narrow footpole. The axial area is very narrow, straight, broadening at the center to form an irregularly rectangular central area. Four isolated stigmoids are present in the central area. The raphe is straight, filiform. Striae appear costate, without resolvable puncta. Apical pore fields appear as condensed striae.

Distribution: Widely distributed in northern sections of North America, usually in circum-neutral to alkaline environments.


Original Description

  • Author
    Tuji 2005

Original Images

Tuji 2005  Plate 15
Tuji 2005

Cite This Page

Kociolek, P. (2011). Gomphoneis pseudo-okunoi. In Diatoms of North America. Retrieved July 22, 2018, from


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Gomphoneis pseudo-okunoi 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.