• Category
  • Length Range
    17.6-31.7 µm
  • Width Range
    6.6-8.3 µm
  • Striae in 10 µm
  • Reported As
    Cymbella silesiaca (Krammer and Lange-Bertalot 1986, plate 117, figs 18-20)



Valves are strongly dorsiventral with curved, subrostrate apices. Apices are oriented ventrally such that the junction between the dorsal margin and the apex is a continuous arc. The dorsal margin is strongly arched. The ventral margin is slightly convex. The axial area is narrow. The central area is a slightly wider continuation of the axial area. The raphe is filiform. Proximal raphe ends are deflected dorsally and terminate in inconspicuous central pores. Terminal raphe fissures are deflected ventrally. Striae are radiate on the dorsal side, a bit farther apart at the valve center than near the apices. The median stria on the dorsal side is next to a signle single isolated areola. The very short striae on the ventral side are parallel at the valve center, then radiate, and finally convergent toward the apices. Areolae in the striae may be resolved in LM and number 30-35 in 10 µm.


The specimens shown on this web page were collected from a stream in Glacier National Park, Montana. Streams in the park typically have low nutrient concentrations, low electrical conductivity, and slightly alkaline pH.

Original Description

  • Author
    Krammer 1997
  • Length Range
    16-38 µm
  • Width
    6.2-11.0 µm
  • Striae in 10µm

Original Images

Encyonema lange-bertalotii orig illus
Encyonema Lange Bertalotii Origdesc003

Cite This Page

Bahls, L. (2016). Encyonema lange-bertalotii. In Diatoms of North America. Retrieved February 28, 2024, from https://diatoms.org/species/encyonema_lange-bertalotii


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