• Category
  • Length Range
    31-37 µm
  • Width Range
    7-9 µm
  • Striae in 10 µm
    22-24 (middle), 36-38 (ends)
  • Synonyms
    Kobayasia okadae (Skvortzov) Lange-Bert.
    Navicula okadae (Skvortzov) Nagumo and H.Kobayasi
  • Reported As
    Navicula hoefleri (Hustedt 1961-1966, p. 97, fig. 1244)
    Navicula hoeflerii (Krammer & Lange-Bertalot 1986, p. 183, fig. 79: 28)



Valves are linear-lanceolate with short, capitate apices. Apices are about one-half the width of the valve. The axial area is narrow and nearly linear, the narrowest point being where the valve margins constrict to form the apices. From this narrow point the axial area flares abruptly towards the valve apex, and, in the other direction, very gradually towards the central area. The central area is small, barely wider than the axial area, and elliptical in shape. The raphe is filiform. A section of each external raphe branch becomes indistinct about mid way between the valve center and the apex. Proximal raphe ends are straight and lie in spathulate depressions, which make them appear expanded in LM. Distal raphe ends are strongly curved towards the secondary side, where prominent Voigt discontinuities are evident in SEM. Striae are radiate, becoming convergent and more closely spaced near the apices. Striae are interrupted by longitudinal hyaline lines, the pair of which form a lanceolate shape within the valve. These hyaline lines terminate near the valve apices, where the striae are not interrupted. The striae also stop short of the valve mantle, where another hyaline line completely encircles the valve along the margins.


Kobayasiella okadae was found among moss and roots of vascular plants in two floating-mat fens in western Montana. Here the pH was 6.77 and 8.46, and specific conductance measured 19 and 257 µS/cm. Elsewhere in the United States, K. okadae has been reported (as Navicula hoefleri) from a few oligotrophic and low conductivity lakes in New York (Camburn & Charles 2000) and Wisconsin (Diatom Paleolimnology Data Cooperative, Patrick Center, The Academy of Natural Sciences). Kobayasiella okadae is typically found together with K. parasubtilissima and K. subtilissima in slightly acid waters in arctic to subarctic zones, and in temperate regions (Nagumo & Kobayasi 1990). Krammer & Lange-Bertalot (1986) reported K. okadae (as Navicula hoeflerii) from Scandinavia and the Alps. Lange-Bertalot & Metzeltin (1996) found K. okadae (reported as Naviculadicta hoefleri) in a Finnish lake that has low levels of conductance and inorganic nutrients and a high level of humic acid.

016 9 A
Credit: Loren Bahls
Drosera Pond, Indian Meadows Research Natural Area, Helena National Forest, Montana: home of Kobayasiella okadae.

Original Description

  • Basionym
    Anomoeoneis okadae
  • Author
    Skvortzov 1938
  • Length Range
    28.9-30.6 µm
  • Width
    6.8 µm
  • Striae in 10µm
    20-22 (middle), 25-30 (ends)

Original Images

Kokadae Origimag
Kobayasiella Okadae  Orig Descr

Citations & Links



Cite This Page

Bahls, L. (2011). Kobayasiella okadae. In Diatoms of North America. Retrieved August 19, 2018, from https://diatoms.org/species/kobayasiella_okadae


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