• Category
  • Length Range
    54.0-75.4 µm
  • Width Range
    11.8-16.7 µm
  • Striae in 10 µm



Valves are linear to linear-lanceolate, with undifferentiated rounded apices. The axial area is narrow and widens abruptly just short of the central area. The central area is a rhombus, open on both sides to form a fascia. The raphe is weakly lateral and slightly complex. Proximal raphe ends are bent to one side and terminate with small tear-shaped pores. Distal raphe fissures are shaped like question marks. Striae are strongly radiate at the valve center and become strongly convergent near the apices.

The shape of this taxon from the Northwest United States is more linear and less lanceolate, than the original European description.

Note that the description of P. suchlandtii first published (Schmidt 1934) was invalid. It was later validly published (Hustedt 1943).


The specimens of P. suchlandtii that are pictured and described on this taxon page are from small lakes in the North Cascades and northern Rocky Mountains. These lakes have cold water, low pH (6.5-7.5) and very low conductivity (7-10 µS/cm). Krammer (2000) reports this species from small, oxygen-rich alpine European lakes with cold waters and low electrolyte content.

Blodgett  Lake By Racarlsen 1
Credit: R. A. Carlsen
Blodgett Lake, Bitterroot Mountains, Ravalli County, Montana: home of Pinnularia suchlandtii.

Original Description

  • Author
    Hust. 1943

Original Images

Pinnularia Suchlandtii Origimag1003
Pinnularia Suchlandtii Origimag2002
Pinnularia Suchlandtii Origimag3001

Cite This Page

Bahls, L. (2014). Pinnularia suchlandtii. In Diatoms of North America. Retrieved May 24, 2024, from https://diatoms.org/species/pinnularia_suchlandtii


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