• Category
  • Length Range
    29.6-45.9 µm
  • Width Range
    5.9-6.9 µm
  • Striae in 10 µm
    16-18 at the valve center, about 20 at the ends on the dorsal side



Valves are linear-lanceolate and nearly symmetric, or barely dorsiventral. The margins are weakly convex to nearly parallel. Apices are subrostrate to broadly cuneate. The axial area is narrow and widens slightly near the central area. The central area is round, symmetric, and formed by shallow depressions on the dorsal and ventral sides. The raphe is lateral, becoming filiform toward the ends. Proximal raphe ends are not expanded and deflected ventrally. Distal raphe ends are hooked toward the dorsal side. Striae are radiate throughout and more widely spaced around the central area. Areolae are difficult to resolve in LM and number 30-34 in 10 ┬Ám.


Together with the nominate variety, Krammer (2003) reports C. incertiformis var. laterostrata as "widely distributed in the subarctic, nordic, and alpine area in oligotrophic to dystrophic habitats with low electrolyte content". Only one record is available from the Montana Diatom Collection: from Loudon Lake in Washington (photos below). Water quality data are not available for this site.

Loudon Lake2
Credit: Ryan Davis, Adventurers and Scientists for Conservation
Loudon Lake, Okanogan County, Washington: home of Cymbopleura maggieae.
Loudon Lake4
Credit: Ryan Davis, Adventurers and Scientists for Conservation.
Closeup of gravelly bottom of Loudon Lake where C. incertiformis var. laterostrata was collected.

Original Description

  • Author
    Krammer 2003
  • Length Range
    24-60 µm
  • Width
    6.5-8.5 µm
  • Striae in 10µm
    15-19 at the valve center, up to 20 towards the apices on the dorsal side

Original Images

Cymbopleura incertiformis var. laterostrata orig desc
Cymbopleura incertiformis var. laterostrata orig illus
Cymbopleura incertiformis var. laterostrata orig descr

Cite This Page

Bahls, L. (2014). Cymbopleura incertiformis var. laterostrata. In Diatoms of North America. Retrieved July 13, 2024, from https://diatoms.org/species/cymbopleura_incertiformis_var._laterostrata


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Cymbopleura incertiformis var. laterostrata 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.