• Category
  • Length Range
    10-29 µm
  • Width Range
    7.0-9.5 µm
  • Striae in 10 µm



Valves are elliptic-lanceolate with rostrate apices. The raphe valve has a narrow linear axial area widening at the valve center into a transversely rectangular asymmetric central area that often reaches the valve margins. The raphe is straight, but its short terminal fissures are gently curved to opposite sides. The proximal external raphe ends are expanded and sharply turned to the same side in SEM, but appear straight in LM. The axial area on the rapheless valve is linear and widens into an asymmetric central area. The striae are uniseriate. The external areolae openings are mostly isodiametric, but transapically elongated near valve margins. Internally, areolae are transapically elongated. There are 23–28 areolae in 10 μm along each stria on the rapheless valve and 28–35 on the raphe valve. The girdle bands are plain and open.


Original Description

  • Basionym
    Achnnathes harveyi
  • Author
    Reimer 1966

Original Images

Achnnathes harveyi orig illus
Achnanthes harveyi orig descr

Cite This Page

Potapova, M. (2012). Psammothidium harveyi. In Diatoms of North America. Retrieved May 18, 2024, from https://diatoms.org/species/psammothidium_harveyi


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