• Category
  • Length Range
    14.0-21.4 µm
  • Width Range
    4.8-5.9 µm
  • Striae in 10 µm
    20-23 at the valve center, 22-24 near the apices



Valves are elliptic-lanceolate and not or only weakly dorsiventral. Apices are rostrate to subcapitate. The axial area is narrow and positioned mid-valve. The central area is small and asymmetric. The raphe is filiform. Proximal raphe ends are not expanded and deflected dorsally. Distal raphe fissures are hooked toward the ventral side. Striae are weakly radiate throughout.


Encyonopsis medicinalis is widespread and locally common in lakes in the Northern Rockies, including Glacier National Park. In these lakes it prefers alkaline water (pH = 7.9-9.1) and low concentrations of dissolved solids (specific conductance = 93-106 µS/cm).

Medicine  Grizzly  Lake 1
Credit: Loren Bahls
Medicine Grizzly Lake, Glacier National Park, Montana: type locality of Encyonopsis medicinalis.

Original Description

Valves elliptic-lanceolate, not or slightly dorsiventral. Apices rostrate to subcapitate. Valve length 14.0–21.4 µm; valve width 4.8–5.9 µm. Axial area narrow. Central area small, asymmetric. Raphe filiform. Proximal raphe ends not expanded, deflected dorsally. Distal raphe fissures hooked toward the ventral side. Striae radiate, 20–23 in 10 µm at valve center, 22–24 in 10 µm near the apices.

  • Author
    Bahls 2013
  • Length Range
    14.0-21.4 µm
  • Width
    4.8-5.9 µm
  • Striae in 10µm
    20-23 at the valve center, 22-24 near the apices

Original Images

Encyonopsis medicinalis orig illus
Encyo Medicinalis Origdesc001

Cite This Page

Bahls, L. (2013). Encyonopsis medicinalis. In Diatoms of North America. Retrieved May 29, 2024, from https://diatoms.org/species/encyonopsis_medicinalis


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