• Category
  • Length Range
    14.6-30 µm
  • Width Range
    6.3-9.1 µm
  • Striae in 10 µm



Valves are linear-elliptic to oval. Raphe valve has a narrow linear axial area and rectangular-irregular central area. Raphe is straight with hook-like proximal ends, drop-shaped distal ends. Rapheless valve has a narrow axial area and an irregular, rounded to rhomboid central area, occupying about ½ of valve breadth. Striae are slightly radiate, 22–25 in 10 μm; shortened marginal striae are present. Areolae are coarse, round, 25 in 10 μm.


So far found only in oligotrophic lakes of Washington Cascade Mountains.

Original Description

  • Author
    Potapova and Enache 2013
  • Length Range
    14.6-30 µm
  • Width
    6.3-9.1 µm
  • Striae in 10µm

Original Images

Psalpinum  Orig Ill
Psalpinum  Orig Descr

Cite This Page

Potapova, M. (2014). Psammothidium alpinum. In Diatoms of North America. Retrieved May 18, 2024, from https://diatoms.org/species/psammothidium_alpinum


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