• Category
  • Length Range
    13-16 µm
  • Width Range
    1.9-2.1 µm
  • Striae in 10 µm
    18-22 in the center valve



Frustules are narrow and rectangular in girdle view. Ventral margins are weakly concave, with two slight swellings marking the position of the proximal raphe ends. Dorsal margins are irregular and weakly triundulate, with the central undulation most prominent. Valve ends are protracted and capitate to subcapitate. Helitoglossae are located close to the apices. The raphe extends in a short curve on to the valve face. Striae are parallel. The areolae are unresolved in the LM. One apical rimoportula is located just above the center of the apex.

Original Description

  • Author
    Krasske 1932
  • Length Range
    10-15 µm
  • Width
    2-3 µm
  • Striae in 10µm

Original Images

Eunotia Microcephala  Orig Ill
Eunotia Microcephala  Orig Descr

Cite This Page

Furey, P. (2012). Eunotia microcephala. In Diatoms of North America. Retrieved June 23, 2024, from https://diatoms.org/species/eunotia_microcephala


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