• Category
  • Length Range
    9.8-16.8 µm
  • Width Range
    3.3-4.3 µm
  • Striae in 10 µm
    14-20 on dorsal; 16-20 on ventral side



Valves are small and moderately dorsiventral, with slightly protracted, rounded ends. The dorsal margin is semi-elliptic. The ventral margin varies, ranging from slightly concave to flat to clearly convex. The raphe is straight and filiform and has inflated, dorsally deflected proximal ends. The distal raphe ends are strongly recurved to the ventral margin. Central striae are somewhat irregular, curved and radiate and lower in density, characteristically with a gap between the ventral central striae. Throughout the rest of the valve, striae transition from weakly radiate to parallel to convergent at the apices.


Encyonema reichardtii has a cosmopolitan distributions among holoarctic rivers and streams. It has been recorded, sometimes in great abundance, in places as varied as East Greenland (Cremer et al. 2001), Luxembourg (Rimet et al. 2004), Bulgaria (Ivanov et al. 2006), the Carpathian Mountains (Noga et al. 2014), Bering Island (Potapova 2014), and in streams throughout the United States (see Google Earth Map below), reaching the greatest abundances in rivers of eastern states.

E Reichardtii  Biodata  Klm Distribution
Credit: USGS BioData
Distribution of Encyonema reichardtii in rivers of the continental U.S. based on the National Water Quality Assessment program. Retrieved 028 June 2017.

Original Description

  • Basionym
    Cymbella reichardtii
  • Author
    Krammer 1985
  • Length Range
    8-12.5 µm
  • Width
    3-4 µm
  • Striae in 10µm

Original Images

Encyonema reichardtii orig illus
E Reichardtii Orig Desc Text

Cite This Page

Bishop, I. (2017). Encyonema reichardtii. In Diatoms of North America. Retrieved July 21, 2018, from https://diatoms.org/species/encyonema_reichardtii


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