• Category
  • Length Range
    10-55 µm
  • Width Range
    2.5-4.5 µm
  • Striae in 10 µm
  • Synonyms
    Nitzschia fonticola Grunow in Cleve and J.D.Möller 1879
    Nitzschia palea var. fonticola Grunow 1880
  • Reported As
    Nitzschia tropica (Hustedt, 1949, p. 147; pl. 11, figs 34-38)
    Nitzschia romano (Hustedt, 1930, p. 415)



Valves are broadly lanceolate with margins parallel and tapering to narrow ends with knob-like, rounded apices. There is prominent gap in the central fibulae, often termed 'central nodule'. The keel is excentric and curves at the apices. Fibulae are distinct and number 10-13 in10 µm. The striae are distinct and parallel.

This taxon is treated as Nitzschia romano Grunow by Hustedt (1930, p. 415). The size range of this taxon is more narrow than reported by Krammer and Lange-Bertalot (1988) our observations.

The taxon Nitzschia tropica Hustedt was described from Africa (former Belgium Congo). The name has been applied - incorrectly - to populations of N. fonticola from the US. Nitzschia tropica is more linear and has a straight raphe (Simonsen 1987, Krammer and Lange-Bertalot 1988), as compared to N. fonticola. Nitzschia tropica has not verified from collections in the US.


Original Description

  • Basionym
    Nitzschia palea var. fonticola
  • Author
    Grunow 1880

EMAP Assessment

EMAP Distribution

Nitzschia Fonticola  Grunow 3
Map 3

Response Plots

Nitzschia Fonticola  Grunow

Cite This Page

Kociolek, P. (2011). Nitzschia fonticola. In Diatoms of North America. Retrieved July 21, 2018, from https://diatoms.org/species/nitzschia_fonticola


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