• Category
  • Length Range
    14-37 µm
  • Width Range
    4.0-4.5 µm
  • Striae in 10 µm
  • Synonyms
    Homoeocladia amphibia (Grunow) Kuntze 1898
    Bacillaria amphibia (Grunow) Elmore in Barbour 1895



Valves are linear to lanceolate. The valves taper to bluntly rounded apices. Fibulae are distinct and number 7-9 in 10 µm. The central nodule is evident. Striae are characteristically prominent and distinctly punctate, but not necessarily regularly spaced.

Original Description

  • Author
    Grunow 1862

Original Images

N Amphibia Orig Description Image
N Amphibia Orig Description Text

Cite This Page

Kociolek, P. (2011). Nitzschia amphibia. In Diatoms of North America. Retrieved May 18, 2024, from https://diatoms.org/species/nitzschia_amphibia


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