• Category
  • Length Range
    14.4-19.6 µm
  • Width Range
    3.3-4.0 µm
  • Striae in 10 µm



Valves are linear to linear-lanceolate with capitate apices. Valves are more or less symmetric along the apical axis. The axial area is narrow. The central area is rounded and variable in size. The raphe is filiform. Proximal raphe ends are weakly expanded and deflected dorsally. Distal raphe fissures are comma-shaped and curved to the ventral side. Striae are radiate throughout.


Encyonopsis hustedtii is widespread and locally common in small streams, springs, and mossy seeps in the Northern Rockies. These waters have somewhat alkaline pH (pH 7.3-8.0) and low to moderate concentrations of dissolved solids (255-411 µS/cm).

Encyonopsis hustedtii is one of many small-celled Encyonopsis and Encyonema species in the Northern Rockies (see plate below). Some of these may be ecomorphs of established species. All of these may be found in Krammer (1997) and Bahls (2013).

Blakiston  Beaver  Pond  A 3
Credit: Barb Johnston, Parks Canada
Blakiston Beaver Pond A, Waterton Lakes National Park, Alberta: type locality of Encyonopsis hustedtii.
Small Encyonopsis Northern Rockies
Credit: Loren Bahls
Small-celled Encyonopsis (E.) and Encyonema taxa from the Northern Rockies. Some of these may be ecomorphs of established species (Bahls 2013, Krammer 1997).

Original Description

Valves linear to linear-lanceolate, not or scarcely dorsiventral. Apices capitate. Valve length 14.4–19.6 µm; valve width 3.3–4.0 µm. Axial area narrow. Central area rounded, variable in size. Raphe filiform, proximal ends unexpanded, deflected dorsally. Distal raphe fissures comma-shaped, curved to the ventral side. Striae weakly radiate throughout, 23–26 in 10 µm.

  • Author
    Bahls 2013
  • Length Range
    14.4-19.6 µm
  • Width
    3.3-4.0 µm
  • Striae in 10µm

Original Images

Encyonopsis hustedtii orig illus
Encyo Hustedtii Origdesc003

Cite This Page

Bahls, L. (2013). Encyonopsis hustedtii. In Diatoms of North America. Retrieved July 13, 2024, from https://diatoms.org/species/encyonopsis_hustedtii


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