• Category
  • Length Range
    27-52 µm
  • Width Range
    6.3-9.0 µm
  • Striae in 10 µm
  • Synonyms
    Navicula cincta var. cari (Ehrenb.) Cleve 1895
  • Reported As
    Navicula graciloides (Patrick and Reimer 1966, p. 516, plate 49, figs. 9-10)



Valves are lanceolate to linear-lanceolate with obtusely rounded to acutely rounded apices. The axial area is very narrow. The central area is laterally expanded and rounded to nearly rectangular. The raphe is filiform with weakly expanded proximal ends that are deflected slightly in the same direction and widely separated. Striae are curved and strongly radiate near the valve center, becoming straight and parallel to convergent near the apices. Areolae are indistinct and number 32 or more in 10 µm.


Navicula cari is widely distributed in lakes, but also in creeks and rivers, throughout the Northwest United States. Here it prefers alkaline, nutrient-rich waters with average to higher conductivity and elevated concentrations of sulfate (see table below). It is usually present in low numbers.

Navcari Chem 001
Credit: Montana Diatom Database
Abundance-weighted means of selected water quality variables measured concurrently with the collection of samples containing Navicula cari.
Lake Levale   Bmw
Credit: Loren Bahls
Lake Levale, Bob Marshall Wilderness, Montana: home of Navicula cari.

Original Description

  • Author
    Ehrenb. 1836

Cite This Page

Bahls, L. (2012). Navicula cari. In Diatoms of North America. Retrieved June 20, 2024, from https://diatoms.org/species/navicula_cari


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