• Category
  • Length Range
    80.2-127.6 µm
  • Width Range
    23.2-28.7 µm
  • Striae in 10 µm
  • Synonyms
    Pinnularia lata (Bréb.) W.Sm. 1853



Valves are linear-elliptic in outline with parallel or slightly convex sides. Larger specimens are somewhat tumid in the middle. Apices are obtusely rounded. The axial area is linear and one-fifth to one-third the valve width. The central area is a rounded asymmetric widening of the axial area. The raphe is broadly lateral and nearly straight, slightly curved in the middle. Near the central nodule the raphe branches are deflected to one side and become filiform. Proximal raphe ends are large and rounded. Distal raphe ends are hook-shaped. The broad, coarse striae are radiate at valve center, becoming parallel or convergent near the apices.


The specimens of Pinnularia lata pictured on this web page were collected from a small lake in the mountains of Haida Gwaii, British Columbia. Krammer (2000) reports this species as widely distributed in northern alpine regions in cool, oxygen-rich, oligotrophic waters with a low electrolyte content, and often found in aerial habitats, seepages over rocks and moss beds, and in torrents.

Original Description

  • Basionym
    Frustulia lata
  • Author
    Bréb. 1838

Cite This Page

Bahls, L. (2014). Pinnularia lata. In Diatoms of North America. Retrieved July 15, 2024, from https://diatoms.org/species/pinnularia_lata


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