• Category
  • Length Range
    25.0-42.0 µm
  • Width Range
    11.5-13.5 at center of valve, 6.5-10 near the apices µm
  • Striae in 10 µm
  • Reported As
    Caloneis schumanniana (Grunow) Cleve (Krammer & Lange-Bertalot 1986, Fig. 171: 4)



The valve margin is triundulate, with the central undulation being slightly broader than the distal undulation. The apices are broadly rounded to cuneate. The axial area is narrow, becoming apiculate toward the apices. The central area is large and rhomboidal in shape with two lunate markings within the central area, on each side of the central nodule. The raphe is straight and filiform near the distal and proximal ends, becoming slightly lateral between them. Proximal raphe ends are slightly expanded. Striae are parallel, becoming radiate toward the central nodule and slightly divergent at the ends.

Krammer and Lange-Bertalot (1986) illustrate a very broad concept of C. schumanniana (Grunow) Cleve which includes C. lewisii. For the US flora, the shape and size series of C. lewisii is treated as distinct at the species level.


Caloneis lewisii thrives in a wide variety of environments ranging from flowing streams to small lakes and ponds in the midwestern U.S., including shallow, temporary waters.

Original Description

Valvae bis constrictae longae 27 µ ad medium 8.7 µ apicibus cuneatae ; striis transversis 19-20 in 10 µ ; area axiali angusto, nodulo centrali majusculo subquadrangularis signis lunatis duobus crasso. Type: Illinois, Du Page County, 2423 F. Drouet, P. C. Standley and J. A. Steyermark (A-2018).

  • Author
    R.M.Patrick 1945
  • Length Range
    27 µm
  • Width
    8.7 µm
  • Striae in 10µm

Original Images

Caloneis lewisii orig illus
Caloneis lewisii orig descr

Cite This Page

Keith, M., Rosen, B. (2012). Caloneis lewisii. In Diatoms of North America. Retrieved April 14, 2024, from https://diatoms.org/species/caloneis_lewisii


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