• Category
  • Length Range
    68-119 µm
  • Width Range
    18-22 µm
  • Striae in 10 µm
    24-26 in the center, 24-25 at the ends



Valves are rhomboid with a very slight constriction near the rounded poles. The striae are parallel at the valve center, wavy near the apices and slightly convergent at the apices. Striae do not circumradiate the apices. The longitudinal striae are parallel at the valve center, but wavy and convergent near the apices. The longitudinal ribs are constricted at the central nodule. The longitudinal ribs fuse with a linear helictoglossa to form a moderate sized porte-crayon. The external proximal raphe ends form small “T” shapes.

These specimens from Goose Lake, Idaho and Island Lake, Washington appear to have more narrowly rounded apices and finer longitudinal ribs than specimens from the type population from Finland (Lange-Bertalot 2001, pl. 128, figs 1-4).

Original Description

  • Author
    Lange-Bert. and Metzeltin 1998
  • Length Range
    96-135 µm
  • Width
    18-24 µm
  • Striae in 10µm

Original Images

Krammeri Oimages
Krammeri Odesc
Original text and images reproduced with permission by ARG Ganter Verlag KG and Koeltz Scientific Books.

Cite This Page

Kociolek, P., Graeff, C. (2011). Frustulia krammeri. In Diatoms of North America. Retrieved June 20, 2024, from https://diatoms.org/species/frustulia_krammeri


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