• Category
  • Length Range
    27-54 µm
  • Width Range
    8-10 µm
  • Striae in 10 µm



Valves are linear and slightly concave in the middle of the valve. The apices are narrow, protracted, and narrowly rounded. The keel is strongly excentric, with the central nodule formed by two fibulae more distant from the others along the keel. Fibulae number 7-9 in 10 µm. A narrow, indistinct fold runs along the longitudinal axis of the valve. The fold is barely undulate or may even appear not to rise or taper from the main valve surface. Transapical ribs are distinct, about 12-16 in 10 µm. Striae are indistinct, seen only with critical illumination.

Stroganov (1927) made the valid transfer of Nitzschia calida Grunow in Cleve and Grunow to Tryblionella before Mann in Round et al. (1990).


Original Description

  • Basionym
    Nitzschia calida
  • Author
    Grunow in Cleve and Grunow; Grunow in Van Heurck 0

Cite This Page

Kociolek, P. (2011). Tryblionella calida. In Diatoms of North America. Retrieved June 21, 2024, from https://diatoms.org/species/tryblionella_calida


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