• Category
  • Length Range
    11.9-27.7 µm
  • Width Range
    5.3-7.2 µm
  • Striae in 10 µm
  • Synonyms
    Navicula diluviana Krasske 1933
    Cymbella diluviana (Krasske) Florin 1971



Valves are lanceolate, with rounded to rostrate apices. The raphe is straight. Proximal raphe ends are externally hooked. At the apices, the distal raphe ends are deflected in the opposite direction of the proximal ends. Striae are somewhat irregularly spaced and vary from radiate to nearly parallel. Striae are more dense near the valve apices and are less dense near the valve center. Porefields are present at both apices, although they may be difficult to resolve in LM.


Populations imaged on this page are from Marl Lake, Waushara County, Wisconsin. Marl Lake is oligotrophic to mesotrophic, with a muddy and sandy bottom. Mean Secchi depth of Marl Lake from 1989-2022 was ~4 m, total phosphorus was 15-30 µg/L, and dissolved oxygen was 1.2-12.8 mg/L.

Original Description

N. diluviana nov. spec. - Abb.2, Fig. 2; Abb. 3 und 4. Schalen elliptsch - lanzettlich mit stumpf vorgezogenen gerundeten Enden, 20 - 30 µ lang, 7-8 µ breit. Axialarea linear, Zentralarea durch VerkÜrzung der mittleren Streifen verbreitert. Streifen radial, in der Mitte weiter (etwa 9 in 10 µ) als an den Enden (bis 14 in 10 µ). Häufige Form des Oderberger Kieselgurgeschiebes.

  • Basionym
    Navicula diluviana
  • Author
    Krasske 1933
  • Length Range
    20-30 µm
  • Width
    7-8 µm
  • Striae in 10µm
    14 at the ends, 9 in the center valve

Original Images

Cymbellafalsa diluviana orig illus 2
Cymbellafalsa diluviana orig illus 1
Cymbellafalsa diluviana orig desc

Cite This Page

Sizemore, C., Stone, J., Mohan, J. (2023). Cymbellafalsa diluviana. In Diatoms of North America. Retrieved June 23, 2024, from https://diatoms.org/species/cymbellafalsa-diluviana


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