• Category
  • Length Range
    142-258 µm
  • Width Range
    21-22 µm
  • Striae in 10 µm
  • Synonyms
    Nitzschia plana var. fennica Hust.



Valves are long and linear, with a barely noticeable constriction in the middle of the raphe side, where the raphe is interrupted. The apices are cuneate and rounded. The striae are parallel and are interrupted by a wide, slightly elevated median area that stretches along the whole valve. Striae vary in length and often continue to the median area as isolated areolae. The external surface of the median area is covered by rounded and irregularly shaped depressions. Groups of 3-7 striae are separated by fibulae, which are approximately 3 ┬Ám long.


This large species was recorded from lake sediments of the northeast US.

Original Description

  • Basionym
    Nitzschia plana var. fennica
  • Author
    Hust. 1924

Original Images

Tryblionella plana fennica origillustr
Tryblionella plana fennica origdescr

Cite This Page

Markarian, D., Potapova, M. (2023). Tryblionella plana var. fennica. In Diatoms of North America. Retrieved July 15, 2024, from https://diatoms.org/species/tryblionella-plana-var-fennica


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Tryblionella plana var. fennica 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.