• Category
  • Length Range
    19.7-57.2 µm
  • Width Range
    7.3-10.9 µm
  • Striae in 10 µm
  • Reported As
    Pinnularia microstauron var. brebissonii (Krammer and Lange-Bertalot 1986, p. 426, fig. 191: 7-9)



Valves are fusiform to nearly elliptic , with parallel margins in larger specimens. The apices are broadly apiculate. The axial area is narrow near the apices, becoming wider toward the central area. The central area is a broad, rhombic fascia. The raphe is weakly lateral and straight. Proximal raphe ends are distinctly inflated and laterally deflected. Terminal raphe fissures are deflected to the primary valve side and are shaped like question marks. Striae are strongly radiate near the central area, becoming parallel, then convergent near the apices.

Pinnularia brebissonii is part of a large species complex, including a number of varieties (Krammer 2000). The specimens here conform to the nominate variety.


The cosmopolitan species Pinnularia brebissonii comprises a large infraspecific complex of varieties, each with rather narrow autecological preferences (Krammer 2000). Specimens of P. brebissonii pictured here are from a shallow alkaline lake in Glacier National Park (photo below) and a cattail marsh adjacent to Interstate 90 in Butte, Montana. The lake, Hidden Meadow Lake, had a pH of 7.82 and a specific conductance of 332 µS/cm.

Hidden Meadow Lake
Credit: Wanderingthewild.com
Hidden Meadow Lake, Glacier National Park, Montana: home of Pinnularia brebissonii.

Original Description

  • Basionym
    Navicula brebissonii
  • Author
    Kütz. 1844

Original Images

N Brebissonii

Cite This Page

Bahls, L. (2014). Pinnularia brebissonii. In Diatoms of North America. Retrieved July 13, 2024, from https://diatoms.org/species/pinnularia_brebissonii


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