• Category
  • Length Range
    31.8-35.5 µm
  • Width Range
    5.8-6.7 µm
  • Striae in 10 µm
    about 40
  • Reported As
    Navicula mandumensis (Camburn & Charles 2000, p. 24, pl. 34, fig. 4; pl. 37, fig. 1)
    Kobayasia madumensis (Lange-Bertalot 1996, p. 282, fig. 18)



Valves are linear-lanceolate with narrow subcapitate apices. Valve length-to-width ratio ranges from 5.2 to 5.6. The axial area is very narrow. The central area is very small and elliptical in shape. The raphe is filiform with weakly expanded proximal ends. Distal raphe fissures are hooked to the same (secondary) side of the valve. Striae are strongly radiate and difficult to resolve in LM. Striae surrounding the central area do not appear to be more widely spaced than striae elsewhere on the valve. Longitudinal lines are absent.


Kobayasiella madumensis was described from a lake in Denmark. The population pictured and described on the identification page was collected from a small sub-alpine lake (elevation 1739 m) in the Mission Mountains of northwest Montana. This lake has a slightly alkaline pH (pH = 7.5) and very low concentrations of dissolved solids (specific conductance = 10 µS/cm). Camburn & Charles (2000) reported this taxon from 34 low-alkalinity lakes in the northeastern United States and Siver et al. (2005) reported it from Cape Cod.

Original Description

  • Basionym
    Navicula madumensis
  • Author
    E.G.Jørg. 1948

Original Images

Navicula Madumensis Orig Desc Plate
Navicula Madumensis Orig Desc Text

Cite This Page

Bahls, L. (2013). madumensis. In Diatoms of North America. Retrieved August 19, 2018, from https://diatoms.org/species/kobayasiella_madumensis


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