• Category
  • Length Range
    30-45 µm
  • Width Range
    9-10 µm
  • Striae in 10 µm
  • Synonyms
    Diadesmis bacillum (Ehrenb.) Kütz. 1844
    Pinnularia bacillum (Ehrenb.) Ehrenb. 1876
    Schizonema bacillum (Ehrenb.) Kuntze 1898



Valves are linear-elongate with rounded apices. The axial area is straight and bordered by a distinct hyaline conopeum. The raphe is straight with rounded and slightly dilated proximal external ends. The distal ends are deflected onto the margin. T-shaped thickenings are present, but indistinct, near the ends. Striae are radiate and arched, becoming parallel at the apices. Striae are broadly spaced at the center of the valve, and become finer (to 22 in 10 µm) at the ends.


Original Description

Cite This Page

Kociolek, P. (2011). Sellaphora bacillum. In Diatoms of North America. Retrieved June 23, 2024, from https://diatoms.org/species/sellaphora_bacillum


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